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A new method of coding polymorphic multiistate characters for phylogenetic analysis is presented. By dividing such characters into subcharacters, their frequency distributions can be represented with discrete states. Differential weighting is used to counter the effect of representing one character with multiple characters. The new method, generalized frequency coding (GFC), is potentially superior to previously used methods in that it incorporates more information and is applicable to both qualitative and quantitative characters. When applied to a previously published data set that includes both types of polymorphic multistate characters, the method performed well, as assessed with g1 and nonparametric bootstrap statistics and giving results congruent with those of other studies. The data set was also used to compare GFC with both gap-weighting and Manhattan distance step matrix coding. On these grounds and for philosophical reasons, we consider GFC to be a better estimator of phylogeny.

To determine the incidence and outcome of neurosensory hearing loss in infants, without selection bias, volunteers screened all infants from intensive care and well-baby nurseries of a tertiary care center for risk factors over 1 year; infants with sufficient risk factors were screened for auditory brainstem evoked response. Infants with abnormal findings received audiometric follow-up. Results of a 1-year follow-up study are reported. Risk factor evaluation revealed a 17% incidence of neurosensory hearing loss in a subgroup of infants with multiple risks such as birth weight less than 1500 gm, with perinatal asphyxia, subsequent hypoxemia, and hospital stay greater than 2 months. All infants with permanent hearing loss were assigned to this category. Our results suggest that this population is at greatest risk for early hearing impairment.

Modern-day perinatal care has resulted in dramatically improved outcomes of premature infants, particularly those weighing 750 to 1,500 gm or of 27 to 32 weeks' gestational age. Assuming that the birth is not traumatic, the infant asphyxiated, or made hypothermic at birth, the chances of the very small premature baby developing normally are great. The delivery of an infant of less than or equal to 32 weeks' gestational age or weighing less than 1,500 gm should occur at a perinatal center when possible.

Red cell volume was measured in 259 infants admitted to a high-risk newborn unit. Red cell volume was measured using 50Cr tagging which subsequently was activated to 51Cr for counting. Total blood volume was calculated using the corrected whole body hematocrit. A low red cell volume was frequently associated with a maternal history of vaginal spotting, with placenta previa or placenta abruptio, with nonelective cesarean section, and with deliveries associated with cord compression. Asphyxiated infants without a history suggestive of blood loos often had a low red cell volume. An early central hematocrit below 45% correlated with a low red cell volume, but a normal or high hematocrit was often associated with low red cell measurements. The total blood volume depended largely on whether the tagging was done long enough after the blood loss for plasma volume equilibration to have occurred. Very low red cell volume values were associated with a high mortality rate, but birth weight played a dominant role in survival, even at low red cell volume levels.

We discuss an infant with hepatitis and hypermethioninemia. An inborn error of metabolism, such as methionine adenosyltransferase deficiency or hereditary tyrosinemia, was originally thought to be the basis for these abnormalities. The infant's subsequent clinical course, however, was incompatible with such a diagnosis; the hypermethioninemia was instead due to the trilogy of prematurity, hepatitis, and a high-protein, high-methionine diet.

Between 1971 and 1973, the frequency of neonatal hypoglycemia was 4.4/1,000 total inborn live births or 15.5/1,000 low-birthweight infants. During that same time, of 257 transferred infants, 13 or 5.1% were hypoglycemic. The hypoglycemic manifestations differed between the inborn and outborn infants as well as from those previously described for transient symptomatic hypoglycemia. This required a new classification for low blood glucose values in the neonate, based on intrauterine nutrition, stress, symptoms, and underlying pathology. Four categories were defined: category I: early transitional hypoglycemia; category II: secondary hypoglycemia; category III: classical transient hypoglycemia; and category IV: recurrent, severe hypoglycemia. One outborn infant was in the latter group due to beta-cell hyperplasia and was only cured after a 90% pancreatectomy. Data revealed that early treatment of perinatal asphyxia was associated with a decreased frequency of hypoglycemia. While not a prospective survey, the evidence suggested that current neonatal intensive care may decrease the frequency of transient symptomatic neonatal hypoglycemia.

A newborn infant with pancreatic beta-cell hyperplasia had persistent hypoglycemia due to hyperinsulinism. After medical management, including the use of diazoxide and constant glucose infusions had proved ineffective, a subtotal pancreatectomy was curative. Cumulative experience seems to indicate that there should be little delay in performing a subtotal pancreatectomy when aggressive medical management cannot maintain normoglycemia in a neonate.

Following an outbreak of group B beta-hemolytic streptococcal neonatal infection (GBS), a prevalence survey of GBS colonization was performed on 238 infants. No important differences were noted in the prevalence of colonization when the infants were grouped according to age. Follow-up of 24 colonized babies for three months disclosed that most had persistence of GBS at the rectum and pharynx. Local umbilical cord care with triple dye (TD) or hexachlorophene skin cleanser was compared with untreated controls with respect to rates of GBS colonization. At birth the colonization rates of the three groups were similar. The rate of acquisition of colonization with GBS was 1.0% in the TD group, 6.3% in the hexachlorophene group, and 8.3% in the control group. Triple dye was much more effective than no specific cord care or hexachlorophene in preventing acquisition of GBS colonization.

During a two-year period, ten infants died suddenly and unexpectedly with a home cardiorespiratory monitor available. We investigated the compliance with appropriate monitoring technique as well as the medical and demographic factors associated with these deaths (90% were due to sudden infant death syndrome). At least six and probably eight of these ten families were noncompliant with appropriate monitoring technique. The main comparison group consisted of 211 patients for whom care with home cardiorespiratory monitors was initiated and continued. Bronchopulmonary dysplasia and severe, apparent life-threatening events were significantly increased in the subjects, as were the following characteristics: black race; lack of private medical insurance; unmarried mother; maternal age of less than 25 years; cigarette smoking by mother during pregnancy; and low Apgar scores. These diagnostic and demographic factors may be useful in predicting the infant at highest risk for sudden and unexpected death when a home monitor is prescribed. Noncompliance with proper monitoring technique patients; methods of educating parents of infants at high risk of sudden infant death syndrome with the necessity for compliance need to be developed.