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The available literature includes conflicting descriptions of the anatomy and function of the oblique retinacular ligament. We have studied this ligament in the index finger to better define its presence, configuration, points of attachment, length, and relationship to the proximal interphalangeal joint axis. Twenty fresh frozen index fingers were dissected. Five additional specimens were decalcified, mounted, sectioned transversely at 1 mm intervals and studied under the microscope. An oblique retinacular ligament was identified on the radial side of the index finger in 95% and on the ulnar side in 90% of the specimens. The radial oblique retinacular ligament was usually longer and more developed than the ulnar oblique retinacular ligament. Proximally, the ligament arose from the middle third of the proximal phalanx and the A-2 pulley whereas, distally, it inserted into the lateral extensor band with a fan-shaped expansion centered 4 to 6 mm distal to the proximal interphalangeal joint line. In 70% of the specimens, the oblique retinacular ligament was supplemented by a contribution from the proximal cruciform pulley (C-1). Histologic cross sections also confirmed the presence of the oblique retinacular ligament but not the supplemental contribution arising from the C-1 pulley. The relationship of the oblique retinacular ligament to the proximal interphalangeal joint axis is dependent on the proximal interphalangeal joint position; the ligament lies palmar to the proximal interphalangeal joint axis only when the proximal interphalangeal joint is flexed.

Within dentistry, a limited body of literature exists regarding the referral relationships between general practitioners (GPs) and specialists. The purpose of this study was to investigate the referral relationship between GPs and periodontists within the state of Virginia.A survey was developed that focused on the demographic variables in the referral relationship between GPs and periodontists. The survey was mailed to 800 dentists throughout the state of Virginia. Descriptive statistics were completed along with multivariate logistic regression analysis comparing the responses with the number of patients referred per month to periodontists.Female respondents were more likely to refer three or more patients per month to a periodontist than a male respondent (P0.02). Those dentists who practiced with one other dentist were twice as likely to refer more frequently when compared to solo practitioners or larger group practices (P0.03). Dentists employing two hygienists were more likely to refer patients than those with fewer hygienists (P0.02). Those whose practices were5 miles from the nearest periodontist were more likely to refer patients compared to dentists geographically closer to a periodontist (P0.02). No other variables had a significant effect on the referral of more patients per month to a periodontist.This study indicates that four demographic variables have a statistical influence on the number of referrals per month from a GP to a periodontist. These variables are as follows: female gender, practicing with one other dentist, employing two or more hygienists, and being5 miles away from the nearest periodontist.

The effects of loading on connective tissues similar to the intervertebral disk have primarily been studied using articular cartilage organ culture in vitro techniques. The effects of in vivo loading on the intervertebral disk are less well documented.The lumbar annuli of rats centrifuged at 2G for 2 wk were compared with those of similar rats kept under analogous conditions at 1G. The studies involved the water, hydroxyproline (collagen), and uronic acid (proteoglycan, PG) content of the L4-5 and L5-6 annuli. Comparisons were also made between the 2G animals and the previous Cosmos 2044 spaceflight animals at 0G.The water content of annuli did not differ between the control and 2G annuli; however, the PG content of the tissue was decreased in the 2G animals and the collagen content slightly increased, resulting in an increased collagen-PG ratio in the 2G animals. When the annuli were immersed in water for 2 h, more PG leached from the annuli of the 2G animals than the control animals, suggesting an alteration in the nature of the PG population comprising the annuli. Interestingly, the direction of changes in the 2G annuli was identical to that of the previous Cosmos 2044 0G animals when they were compared with their respective controls. Therefore, directly opposite experimental conditions (2G and 0G) produced similar results.Previous studies regarding PG synthesis and content in cartilaginous tissues suggest alterations in intratissue pH and hydration to be among the factors involved in controlling the PG population. If the observed changes are permanent, they may affect the integrity of the intervertebral disk although it is likely they are totally reversible on return to 1G after an interim period, providing injuries are avoided.

To determine the effects of intense exercise on the growth of long bones in immature animals, young male white leghorn chickens were run five days per week starting at four weeks of age on motor-driven treadmills. Work intensity was determined on the basis of maximal oxygen consumption (VO2 max) with the exercise intensity maintained at 70-80 percent VO2 max. Young animals ran continuously for 30 minutes, older animals 45 to 60 minutes each day. Runners and controls (10 animals per group) were sacrificed at 8, 12, 14 and 20 weeks of age. The lengths of the femurs and tibiotarsus were significantly stunted at 8-, 12- and 14 weeks in the runners but had nearly recovered at 20 weeks of age. Both bones also demonstrated significantly decreased total cross-sectional areas in 8-, 12- and 14 week-old runners as well as decreased cortical cross-sectional areas. The tibiotarsus also remained significantly smaller in the 20-week-old runners, but the femur had recovered in terms of radial growth. Intermolecular pyridinoline collagen crosslinks were identical in amount in the two groups with the femur collagen significantly less cross-linked than the tibiotarsus. The delayed growth of the exercised avian young bone is consistent with data obtained from children and young mammalian models. The osteogenic response to exercise that produces an increased bone mass in adult tissue appears either suppressed or overcome in young avian bone indicating that it may be erroneous to assume that data obtained from adult tissue are also applicable to young growing bone.

Delmopinol has been considered as a potential agent for the chemical control of plaque. The aims of these studies were to measure the effects of a 0.2% delmopinol hydrochloride mouthrinse on (1) plaque reformation and (2) salivary bacterial counts. Comparisons were made with a 0.2% chlorhexidine rinse and a placebo rinse. A group of 12 male volunteers took part in the plaque study which was of a double blind, randomised, 3 cell, cross-over design. From a zero plaque baseline subjects rinsed, 2x a day, under supervision, for 1 min with 10-ml volumes of the allocated rinse. After 4 days, during which no other form of oral hygiene was performed, plaque was scored by area and index. Plaque results were significantly lower with chlorhexidine and delmopinol compared with control, and with chlorhexidine compared to delmopinol. Side-effects with delmopinol were transient tingling and numbness of the tongue in some subjects. A 2nd group of 12 male volunteers received single, 1-min rinses of the 3 formulations. Salivary bacterial counts were determined immediately before and up to 420 min after rinsing. Compared to the control rinse, chlorhexidine significantly reduced bacterial counts of 420 min. Delmopinol produced a small reduction in bacterial counts which was only significantly different from control at one time point. Delmopinol deserves further evaluation as a chemical plaque inhibitor, particularly when used as an adjunct to normal toothcleaning.

The lumbar annuli of rats flown on COSMOS 2044 were compared with those of three control groups and a tail-suspension experimental model. The wet and dry weights of the annuli were significantly smaller (P less than 0.05) in the flight group than in three control groups. The collagen-to-proteoglycan ratio was significantly greater (P less than 0.001) in the flight group than in the three control groups, but there were no detectable changes in the relative proportions of type I and II collagen or in the number of pyridinoline cross-links. When the annuli were immersed in water for 2 h, more proteoglycans (P less than 0.001) leached from the annuli of flown rats than from the tissue of control animals, suggesting abnormal or smaller proteoglycans. Safranin-O indicated a normal spatial distribution of the proteoglycans within the annulus. Tail suspension did not affect the size of the annuli, but more proteoglycans (P less than 0.05) leached from the tissue of suspended animals than from the normal annuli. The reasons for smaller disks and the abnormal ratio between the fibrous collagenous network and the proteoglycan gel in the flight group are unknown at this time. It is, however, probable that these changes may affect the biomechanical functions of the annulus, although they may be temporary and totally reversible if injuries are avoided in the interim period.

Summary Three cases of tumour of the accessory lobe of the parotid gland are reported and the surgical aspects discussed. An approach through a routine parotidectomy incision is preferred to direct incision over the mass.

Seven muscles in the velopharyngeal region of humans were studied histologically to determine the presence of muscle spindles. Typical spindles were found in palatoglossus and tensor veli palatini with a greater number in the latter. Spindles were not found in levator veli palatini, palatopharyngeus, musculus uvulae, salpingopharyngeus, or the superior pharyngeal constrictor.

The metaphyseal dysostosis growth plate matrix was examined by alcian blue-magnesium chloride histochemistry and electron microscopy. The metaphyseal dysostosis matrix is uniformly alcian blue positive at all molarities of MgCl2 up to 1.0 M. In normal growth plates, the vertical septa become alcian blue negative at 0.5 to 0.6 M MgCl2. At 1.0 MgCl2, metaphyseal dysostosis plates are weakly periodic acid-Schiff (PAS) positive compared to intense PAS reactions in normal growth plates. The histochemical findings correlate well with the decreased collagen content of the matrix as seen by electron microscopy, resulting in a relative increase in proteoglycan granules. The findings indicate that the previously described cellular defect seen in metaphyseal dysostosis chondrocytes is related to an abnormal cartilage matrix that mineralizes poorly and is not easily degraded.

The activities of acid and alkaline phosphatases were significantly increased in subcellular fractions isolated from the aorta of deoxycorticosterone-acetate induced hypertensive rats as compared to normotensive Sprague-Dawley rats. Calcium uptake by the microsomal vesicles of deoxycorticosterone-acetate induced hypertensive rats was slightly reduced as compared to normotensive Sprague-Dawley rats, particularly in the presence of 10 μ m free CaCl 2 . Total tissue Ca 2+ content in the aortae was significantly increased in deoxycorticosterone-acetate induced hypertensive rats as compared to normotensive Sprague-Dawley rats. These results suggest that increased activities of phosphatases in the vascular smooth muscle may be representative of biochemical alterations occurring in the deoxycorticosterone-acetate-hypertensive rats.

Male white Leghorn chickens were exercised on a treadmill at 70-80% of their maximal oxygen consumption starting at 4 weeks and continuing up to 20 weeks of age. The effect of the strenuous exercise regime on the extracellular matrix of menisci was followed through studies of proteoglycans and collagen. Avian menisci contain type I collagen, chondroitin sulfate proteoglycans, which increase with age in amount and degree of aggregation, and dermatan sulfate proteoglycans, which decrease with age. Five weeks of exercise cause a premature decrease of dermatan sulfate proteoglycans, while the chondroitin sulfate-containing molecules become significantly more aggregated than those of the tissue of age-matched controls. Strenuous exercise also causes a significant decrease in the number of pyridinoline crosslinks per mole of collagen in the menisci of young runners. The exercise-induced changes of proteoglycan and collagen occur only during the period of active growth, and all parameters return to normal when the animals reach skeletal maturity. The early proteoglycan aggregation and dermatan sulfate decrease induced by exercise are probably an adaptation to the increased loading. Although the mechanism by which strenuous exercise reduces or delays the formation of collagen pyridinoline crosslinks in menisci of skeletally immature animals is unknown, their decrease could negatively affect the mechanical properties of the tissue during the period of active growth.

Interrupted and continuous microsuturing techniques were compared 3 weeks after microarteriorrhaphy in the rat femoral artery using light microscopy, and internal luminal diameter determinations were measured with a Bio Quant II Digitizer. The histologic appearance of the arteries of both groups was similar, with intimal hyperplasia, intimal incorporation of suture projections into the lumen, minimal inflammatory response to suture material, and restoration of the media. No significant difference was demonstrated between internal diameters at the anastomosis site for the continuous (N = 11, mean diameter 804 +/- 60 microns) and interrupted (N = 11, mean diameter 901 +/- 45 microns) groups. However, the experimental arteries in both continuous and interrupted groups were significantly dilated when compared to their controls (513 +/- 41 microns and 621 +/- 44 microns, respectively). This study indicated that interrupted and continuous suture techniques in laboratory microarteriorrhaphy result in similar histologic and morphologic characteristics, and that the repaired vessels were dilated compared to intact vessels.

Of 3,816 homosexual men examined in five sexually transmitted disease clinics in the United States, 6.1% had hepatitis B surface antigen, 52.4% had antibody to hepatitis B surface antigen, and 3.0% of the men who had no other indicator of infection with hepatitis B virus (HBV) had antibody to hepatitis B core antigen. The rate of seropositivity for HBV indicated by the presence of one or more of these serologic markers was 61.5%; seropositivity was significantly related to the duration of regular homosexual activity and to the number of nonsteady male sexual contacts in the four months before the patients were interviewed. Anal-genital intercourse, oral-anal intercourse, and rectal douching were significantly related to evidence of HBV infection, but oral-oral contact and oral-genital contact were not. Trauma to the rectal mucosa is a feature common to the practices that were significantly related to seropositivity for HBV.

Samples of aortae and caudal arteries from normotensive and hypertensive rats were studied for cytochemical and biochemical determinations of acid and alkaline phosphatase activities. Cytochemical examination revealed an increased amount of acid phosphatase reaction product in hypertensive samples, with extensive localization to the extracellular matrix. Alkaline phosphatase activity was localized to the plasma membrane of fibroblasts and vascular smooth muscle cells and to the extracellular matrix. Biochemical assays of enzyme activities supported the cytochemical findings, showing increased activity in aortae from hypertensive rats.

OTITIS media is the second highest cause of morbidity among Alaska natives.1 This and other reports of unusually high rates of hearing deficiency2'3 have stimulated a series of projects to investigate the natural history and epidemiologic concepts of middle ear disease. In a pilot study which compared the retrospective history of draining ears and the prevalence of hearing deficiency among Eskimo, Aleut, and Caucasian children in Alaska, Eskimo children had the greatest prevalence of pathology.4 The present study correlates episodes of otorrhea and hearing deficiency in a cohort of Eskimo children who have been followed since their birth.

The morphological effects of daily bouts of exercise and denervation on teres minor intrafusal muscle fibers were investigated in male Sprague-Dawley rats. After denervation, nuclear bag and nuclear chain muscle fiber cross-sectional area atrophied only 25 and 33% of the amount experienced by extrafusal fibers. Of the two fiber types, the nuclear chain fibers appeared to be more responsive to the effects of exercise than the nuclear bag fibers; however, this trend for enlargement had no statistical significance. Length measurements did not reveal any marked changes of any fiber type to the experimental conditions of this study. It was concluded that the possible differences in function and innervation of the nuclear bag and nuclear chain fibers could partly account for these findings.

We studied the location and ultrastructure features of rat teres minor intrafusal muscle fiber satellite cells. They were abundant in myotube and polar regions, particularly near sensory nerve terminals and terminations of the spindle capsule and intrafusal muscle fibers. One satellite cell was wedged between two “paired” nuclear bag fibers in the myotube region. No basement membrane surrounded this cell. A polar satellite cell was encased by the basement membrane for only part its length. This cell contained numerous myofilaments. It terminated in the intercellular space surrounded by its own basement membrane adjacent to the host nuclear bag fiber. Recent satellite cell investigations are summarized and compared with the results of this study. We conclude there may be more than one cell type in the satellite cell position and intrafusal and extrafusal satellite cells may function in different capacities.

Five pleomorphic, one monomorphic adenoma and one acinic cell lower pole parotid tumours were thought to be lymph nodes and enucleated. Wide excision of the operative site within 2 months revealed microscopic recurrence in three cases. Three carcinomas were enucleated and two had recurred rapidly. It is suggested that such cases of inadvertent enucleation should undergo wide resection of the operative site with nerve dissection.

A series of 336 parotidectomies, carried out for benign disease has been followed for up to 20 years. One hundred and thirty primary pleomorphic adenomas were treated by wide excision of the tumour after identification of the facial nerve. Recurrence occurred in only one patient and, although 20 patients (15 per cent) experienced some degree of facial nerve weakness postoperatively, there was only one case of permanent weakness.

A delta virus (DV) infection was experimentally transmitted to a hepatitis B chronic carrier chimpanzee. The infection was monitored by the examination of liver biopsy materials with the use of FITC-labeled human anti-delta IgG or by an indirect immunoperoxidase staining technique and by measurement of the serum alanine aminotransferase (ALT) activity. Three different antibody enzyme immunoassays (EIAs) were developed for assessment of the serologic response: 1) blocking assay, 2) IgM-specific capture assay, and 3) IgG-specific capture assay. An antigen-specific EIA was also developed for monitoring delta antigen in the serum. The results indicate that a superinfection with the DV produced a biphasic ALT response concomitant with the appearance of the delta antigen in biopsy materials. The persistence of these markers over the observation period (350 days) indicates the development of a persistent DV infection.

In the time course of the infectious process, 239 patients with acute hepatitis B, 220 patients with chronic hepatic diseases with HBs-antigenemia and carriers of HBs-Ag were tested for the presence of HBe-Ag were tested for the presence of HBe-Ag and antibody to it using double immunodiffusion test (DID) and radioimmunoassay (RIA) or enzyme-labeled immunosorbent assay (ELISA). At high HBs-Ag concentrations determined by DID the HBe antigen was found significantly more frequently than at low concentrations detectable by the sensitive tests only, whereas antibodies to HBe were detected more frequently at low concentrations of HBs-Ag. In patients with acute hepatitis B examined in the first week after the onset HBe-antigen was found in 85.8% cases (38.9% by DID and 46.9% by RIA or ELISA alone). The HBe-antigen could be detected for over 2 months after the onset in 3.6% of the patients in whom the pathological process was becoming chronic. A correlation between the e-system detection and the clinical course of the disease was established: in severe forms, e-antigen concentrations detectable by DID were observed significantly more frequently than in mild (16.7%) or moderately severe (29.2%) forms, and at the same time e-antibody was found more frequently (28.6% against 12.5 and 10.4%, respectively) early in the acute period. The early appearance of HBe-antibody in fulminant course of acute hepatitis B was typical mainly in babies of the first 6 months of age (75%) and in the majority of the cases was indicative of immediate unfavourable prognosis.

To determine the relative occurrence of hepatitis A, B, and non-A/non-B in the United States, serum samples and epidemiologic data were collected from patients with hepatitis in five selected counties. Overall, 41, 33, and 26 percent of the patients had hepatitis A, hepatitis B, and hepatitis non-A/non-B, respectively. The incidence, especially of hepatitis A, varied considerably. All three types of hepatitis occurred more frequently in those 15 to 44 years of age. Hepatitis A predominated in those less than 15 years of age and non-A/non-B predominated in those older than 44 years. There was a male predominance (65 to 62 percent) for hepatitis A and hepatitis B, but non-A/non-B occurred equally in both sexes. There was no seasonal pattern for any type. Risk factors for hepatitis A were previous contact with a patient with hepatitis (26 percent), homosexual (male) preference (15 percent), and day-care center contact (11 percent). For hepatitis B, risk factors included drug use (26 percent), previous contact with an infected person (22 percent), homosexual preference (12 percent), and a health-care occupation (12 percent). For hepatitis non-A/non-B, risk factors included drug use (16 percent), transfusion (12 percent), and previous contact with an infected person (12 percent). Previous hospitalization appeared to be a risk factor for both hepatitis B and hepatitis non-A/non-B.

The tissue factor (thromboplastin) activity of cells grown in vitro is modulated by exogenous drugs. The activity of human foreskin fibroblasts and umbilical vein smooth muscle cells is enhanced by 10(-6) M hydrocortisone or 1 mM butyrate. Activity is suppressed in these cells by 10(-6) M colchicine whereas 10(-4) M chloroquine has little or no effect. Two established cell lines, WISH or HeLa cells, have elevated tissue factor activity in the presence of colchicine or chloroquine and suppressed activity with exogenous hydrocortisone. Their activity is also decreased by 10 mM butyrate whereas 1 mM butyrate does not alter activity. Colchicine and butyrate apparently act via a mechanism unrelated to their effect on microtubules since it is possible to dissociate activity changes from morphologic changes. Umbilical vein endothelial cell tissue factor activity responds uniquely to exogenous drugs. Hydrocortisone or 10(-5) M vinblastine (or colchicine) only minimally alters activity. Endothelial cells are not simply refractory toward all drugs, however, since chloroquine dramatically enhances activity whereas 1 mM butyrate suppresses it. The low specific activity of endothelial cells and their apparently unique drug response may be another measure of their function as an in vivo hemostatic barrier.

The risk of the spread of hepatitis B virus infection from deinstitutionalized, mentally retarded carriers to pupil and staff school contacts in the New York City public school system was measured serologically in a three-phase study from 1978 to 1982. In the third phase, undertaken in 1982, blood samples were drawn and questionnaires were completed on students and staff tested in either of the first two phases and on comparison groups with intermediate and no known school exposure to deinstitutionalized carriers. Univariate and logistic regression analyses revealed that staff and pupils with a history of classroom exposure to a hepatitis B virus carrier had significantly increased prevalences of hepatitis B virus infection (13.4%, odds ratio = 1.9; 9.3%, odds ratio = 2.5, respectively). Similarly, yearly seroconversion rates of 1.3% and 0.67% indicate that staff and, to a lesser extent, pupils are at increased risk of infection.

Hepatitis A is a disease of worldwide distribution which occurs in endemic and epidemic form and is transmitted primarily by person-to-person contact through the fecal-oral route. Common source epidemics due to contamination of food are relatively common, and water-borne epidemics have been described less frequently. The presumed etiologic agent of hepatitis A has now been visualized by immune electron microscopic (IEM) techniques in early acute-illness-phase stools of humans with hepatitis A as well as in chimpanzees experimentally infected with material known to contain hepatitis A virus. In addition, several new serologic tests for the detection of antibody against hepatitis A virus have been described. These include complement fixation and immune adherence techniques. Current data suggest that hepatitis A is caused by a single viral agent lacking the morphologic heterogeneity of hepatitis B viral components and that there may be relative antigenic homogeneity between strains of virus recovered from various parts of the world. Serologic studies to date also indicate that hepatitis A virus is not a major contributing cause in post-transfusion hepatitis. ImagesFIG. 2

A double-blind study was conducted to assess the influence of a sclerosing solution on rabbit medial collateral ligaments (MCL) in situ. It was shown that repeated injections of 5% sodium morrhuate into the MCL and its bony attachments significantly increased its bone-ligament-bone junction strength, ligament mass and thickness when compared to saline-injected controls. Morphometric analysis of electron micrographs showed a highly significant corresponding increase of the collagen fibril diameters in the experimental ligament compared against the control MCL. These composite findings suggested that the sclerosing solution had a significant influence on dense connective tissue at the insertion sites. The mechanisms for these changes are uncertain and are the basis for future investigations.

In 1973, epidemiologic and serologic data related to hepatitis B infection were collected from the residents of two remote Alaskan Eskimo villages located in an area of high hepatitis incidence. A total of 418 sera were tested by solid-phase radioimmunoassay for heaptitis B surface antigen (HBsAg) and antibody to that antigen (anti-HBs). The overall infection prevalence of 54.8% in the two villages included a 13.9% prevalence of HBsAg and a 40.9% prevalence of anti-HBs. Families containing an individual with HBsAg had significantly higher infection prevalence than those without an antigen carrier. Larger households had higher proportions of infected members than smaller households. The data suggest that efficient transmission of hepatitis B virus occurs within the household setting in these villages by other than classically established parenteral routes.

Core biopsy specimens of the proximal femoral growth plate from three patients with slipped capital femoral epiphysis were studied by light and electron microscopy. In the resting zone, the cartilage matrix was composed of large, densely packed collagen fibrils. The cartilage matrix in the zones of chondrocyte hypertrophy where the slippage occurred contained only scattered fine collagen fibrils in a homogeneous ground substance. The change in composition of cartilage matrix in the distal region of the epiphyseal plate may predispose that region to slippage.

To define the epidemiologic features of occupationally acquired hepatitis B infection among physicians, we conducted a seroepidemiologic survey of physicians attending three American Medical Association conventions in 1975 and 1976. Of 1,192 participating physicians, 220 (18.5%) had serologic evidence of prior hepatitis B virus infection (positive hepatitis B surface antibody). The infection rate was higher among those practicing in urban communities; it increased with the number of years in practice; and among specialties, it was highest in pathologists (27%) and surgeons (28%). The serologic data demonstrated a changing pattern of viral hepatitis related to entry into the medical profession, with hepatitis B accounting for a majority of clinical hepatitis experienced after beginning medical practice.

Seven cases of synovial sarcoma were studied by electron microscopy. The 4 cases of the monophasic spindle type contained elongated cells arranged in sheets and cords; ultrastructurally the cells contained many cytoplasmic processes and were scattered in an amorphous matrix. The monophasic spindle type demonstrates ultrastructural characteristics that are unique and serve to differentiate it from the biphasic pattern and from fibrosarcoma. Three cases of the biphasic variety demonstrated cytologic characteristics of a true glandular epithelium and a malignant spindle cell stroma. The epithelial nature of the biphasic variety is a feature that raises doubt whether synovium is the stem cell.

To determine if heterosexual activity was a risk factor for acquiring hepatitis B virus (HBV) infection, we studied attendees at a sexually transmitted disease (STD) clinic and students at a large university. Responses to self-administered questionnaires were used to exclude persons with factors known to be related to the acquisition of HBV and to determine the number of recent (past four months) and lifetime sexual partners. Serum samples were tested for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. For white heterosexuals in the STD group, the prevalence of HBV infection was 6% for those with fewer than five recent partners vs 21% for those with five or more partners, and 5% for those with fewer than 50 lifetime partners vs 20% for those with 50 or more partners. For black heterosexuals in the STD group, no association was found between prevalence of HBV infection and number of recent or lifetime sexual partners. For the heterosexual student group (all white), the prevalence of HBV infection was 1.5% for fewer than three recent partners vs 14% for three or more partners, and 2% for fewer than ten lifetime partners vs 7% for ten or more partners. For white heterosexuals, the risk of acquiring HBV infection increases with increasing amounts of sexual activity and may reach a level similar to that of other groups previously recognized to be at high risk of acquiring hepatitis B.

A forty-four-year-old white man had a stout rubber cable extruding 2 cm. from the external urethral meatus. He had introduced an 82-cm. rubber cable via his urethra into his bladder to assist in clearing dysuria and hematuria. Suprapublic removal of the rubber cable was accomplished, and his postoperative course was benign.

The occurrence of a common source hepatitis A epidemic among the residents of a New England state mental institution where hepatitis B is hyperendemic provided an opportunity to observe concurrent infections with both agents. Nine HBsAg-positive individuals developed hepatitis A infections documented by hepatitis A antibody seroconversion in eight. The incidence of hepatitis A infections in susceptible HBsAg-positive persons (67%) did not differ from that in HBsAg-negative individuals (63%). The icteric to anicteric infection ratio in the HBsAG-positives (1:1.7) was similar to that in the negatives (1:2.1), and the clinical course in the antigen positives did not differ significantly from that of the antigen negatives. In addition to confirming previous reports that the viruses of hepatitis A and B are immunologically distinct, these results document that infection with either is independent of the other, and that the morbidity from simultaneous infection is no greater than that caused by either alone.

Serum levels of alpha-fetoprotein (AFP) may be raised for up to 2 years before clinical presentation of primary hepatocellular carcinoma (PHC). A group of people judged to be at high risk of PHC because of long-term serological positivity for hepatitis B surface antigen, ethnicity, location of residence, and a strong family history of PHC were screened for increasing levels of AFP. After 1 1/2 years of twice-yearly screening, one of them, a 19-year-old Eskimo man, had a raised AFP level, which continued to rise rapidly over the next 3 months, although the patient remained symptomless and ultrasonography, 99mTc-scan, and computerised tomography of the liver were negative. Hepatic angiography suggested a small tumour in the periphery of the right lobe of the liver, but at laparotomy the right lobe was normal. Instead a tumour was found in the lateral tip of the left lobe. The tumour, a PHC, was resected surgically, and the patient has been well in the 11 months since his operation. His serum AFP level returned to normal 2 weeks after the operation and has remained normal.

Ultrastructure features of muscle spindles from two patients with myotonic dystrophy are described. Intrafusal muscle fibers exhibit extensive splitting with nuclear bag fibers affected more so than nuclear chain fibers. No sensory endings are present on nuclear chain fibers nor on one nuclear bag fiber throughout the equatorial and myotube regions. Small motor end plates are evident on various segments of split intrafusal fibers in the polar region and some of these extend into the myotube region. Satellite cells are numerous on both nuclear bag and nuclear chain fibers. These frequently occupy the cleft space between segments of split intrafusal fibers. The myotonic dystrophy muscle spindle ultrastructure features seem to closely resemble the appearance of developing mammalian muscle spindles as illustrated with opossum fetal tissue.

Between April 1, 1984, and Feb 1, 1985, nine cases of hepatitis B occurred in the patients of a dentist practicing in a rural Indiana county (population, 35,000). This was over 20 times the mean annual incidence for the county in the previous decade. All of the patients had been treated by the dentist two to five months before illness. Although the dentist had never had hepatitis symptoms, his serum was positive for hepatitis B surface antigen and hepatitis B e antigen and negative for anti-hepatitis B core IgM antibody, indicating that he was probably a hepatitis B carrier. Two patients (22%) died of fulminant hepatitis; the case-fatality ratio was over ten times the reported US mean for hepatitis B. Using a case definition based on anti-hepatitis B core IgM antibody positivity and exposure to the dentist during a defined time period, a serosurvey of the dentist's patients identified 15 asymptomatic cases (overall attack rate, 3.2%). Infection risk was related to the amount of trauma involved in the cases' dental procedures. No cause was found for the unusual lethality of the outbreak.

In 25 human intervertebral discs studied by electron microscopy, sheathing collagen-like fibrils by electron-dense cylinders was observed. The sheaths consisted of layers of dense granules 3 to 12 times the diameter of the enclosed collagen-like fibrils, and they appeared to be more frequent in older discs.

To elucidate the pathogenesis of calcifying tendinitis, clinical and morphological investigations were done on 46 surgically treated cases. Contrary to the prevalent concept of degeneration preceding dystrophic calcification, we found no evidence for an active or a healed degenerative process. The affected tendon was transformed into fibrocartilage with a predilection for calcification. The formative phase of calcification was followed in course of time by a resorptive phase during which the deposits were surrounded by phagocytosing cells. There was a concomitant proliferation of vascular channels. We found a significant correlation between severe pain and histological signs of resorption. The pathogenetic mechanism of calcifying tendinitis should be reassessed as a unique disorder of the musculotendinous cuff.

Between January 1984 and December 1985 a large outbreak of viral hepatitis occurred in the island nation of Mauritius (population 986,000). No hepatitis epidemics had occurred there since the 1930s. The outbreak involved 2428 reported cases; however, reporting levels were thought to be extremely low. All of the island's nine geographical districts were affected, but cases were concentrated in five districts mostly in the central and northern parts of the island. The highest attack rate occurred in children aged five to nine; persons above age 14 were almost unaffected. The male:female ratio of cases was 1.1:1. Evidence to support hepatitis A virus (HAV) as the infecting agent included; (1) clinical illness was compatible with hepatitis A; (2) the age profile of cases was typical for community-wide hepatitis A outbreaks; (3) the rate of positive tests for hepatitis B surface antigen in suspected hepatitis patients did not increase during the outbreak; and (4) nine of nine clinically ill children tested were serum-positive for IgM anti-hepatitis A virus antibody. Transmission was probably by the person-to-person route; no common source was implicated. The outbreak appears to represent a transition from a 40-year pattern of endemic HAV transmission on the island to an epidemic pattern.