No association between body mass index and beta(3)-adrenergic receptor variant (W64R) in children with premature pubarche and adolescent girls with hyperandrogenism.

OBJECTIVE: To determine if the Trp(64)Arg (W64R) variant of the beta(3)-adrenergic receptor (ADRB3) could be used as a genetic marker to define risk for polycystic ovary syndrom (PCOS) and/or obesity in children and adolescents. DESIGN: Association study. SETTING: Academic research environment. PATIENT(S): Children referred for evaluation of premature pubic hair (n = 63), adolescent girls referred for evaluation of hirsutism and/or oligomenorrhea (n = 33), and healthy adult controls (n = 67). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Relationship of body mass index (BMI) to presence or absence of W64R variant and frequency of W64R variant in our patient population. RESULT(S): Body mass index (kg/m(2)) was determined for 63 children (55 girls and 8 boys) and 33 adolescent girls. Presence or absence of the W64R variant was assayed by polymerase chain reaction (PCR) amplification followed by allele-specific restriction fragment digest. Twelve subjects and 11 healthy controls were found to be heterozygous for the W64R variant. One subject was found to be homozygous for the W64R variant. Allele frequency for the W64R variant was comparable between patients and controls. Among the patients, mean BMI values were not different between carriers and noncarriers. CONCLUSION(S): Although other studies suggest that the W64R variant is associated with the development of obesity and insulin resistance, we cannot demonstrate that it has a major effect on BMI in children with premature pubarche or in adolescent girls with hyperandrogenism. Serial observations are necessary to determine if this variant predicts the development of obesity and/or PCOS in adulthood.

Absence of microdeletions in the Y chromosome in patients with a history of cryptorchidism and azoospermia or oligospermia.

OBJECTIVE: To determine if cryptorchidism is associated with microdeletions of interval 6 of the Y chromosome, we evaluated this locus in men with a history of cryptorchidism with and without azoospermia or oligospermia and in a control group. DESIGN: Clinical study. SETTING: Academic research environment. PATIENT(S): Men in whom surgical treatment of cryptorchidism had been performed in childhood and healthy control male subjects. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Genotyping of interval 6 of the Y chromosome. RESULT(S): Analysis of semen obtained from men treated for cryptorchidism in childhood showed azoospermia or oligospermia in 14 of 38 (37%) men. No microdeletions were identified with polymerase chain reaction amplification of 17 distinct sequence tagged sites located on the long arm of the Y chromosome and the sex determining region on Y (SRY) gene. CONCLUSION(S): Microdeletions of interval 6 of the Y chromosome were not detected in either the formerly cryptorchid or in the healthy subjects. Although we cannot exclude the possibility of point mutations, we conclude that cryptorchidism or cryptorchidism associated with azoospermia or oligospermia is not due to microdeletions involving interval 6 of the Y chromosome.

Assessment of ventilation during the performance of a percutaneous dilatational tracheostomy: hypoventilation is not a common complication.

Percutaneous dilatational tracheostomy (PDT) is becoming an accepted cost-effective alternative to surgical tracheostomy. PDT is performed by progressive dilatation of a tracheal opening placed under bronchoscopic guidance. Case reports of hypoventilation with associated hypercarbia during the performance of PDT have raised concerns about the utility of this procedure in patients in whom hypercarbia is problematic (e.g., patients with closed head injury). In a prospective cohort analysis of 11 critically ill patients, we evaluated the effect of PDT on ventilation during and after the procedure using end tidal capnography. We found that hypercarbia does not occur during or after the performance of PDT as compared to baseline levels.

Utility of a bedside Doppler in tracking left ventricular dysfunction related to hemorrhagic shock.

Treatment of hemorrhagic shock with fluid resuscitation alone results in diastolic dysfunction as measured by peak systolic pressure/end systolic volume ratio (PSP/ESV). The purpose of this study was to test the ability of a simple Doppler device to track diastolic dysfunction in hemorrhagic shock. In this prospective, controlled crossover study, five adult swine were resuscitated from hemorrhagic shock using fluids. Diastolic dysfunction was confirmed using PSP/ESV ratio. The effect of nitroprusside and dobutamine on this diastolic dysfunction was evaluated. Data (PSP/ESV, Doppler-derived acceleration, and oxygen transport parameters) were collected at each stage of the model. Arterial pressure and oxygen transport parameters corrected to baseline values; however, the PSP/ESV and Doppler-derived acceleration failed to correct with fluid resuscitation alone. Treatment with nitroprusside and dobutamine increased oxygen transport parameters, PSP/ESV ratio, and Doppler-derived acceleration significantly. Doppler-derived acceleration tracks left ventricular dysfunction seen in hemorrhagic shock.

The effect of severe closed head injury on the incidence of nosocomial infections.

Severe closed head injury is a common problem seen with trauma patients. These patients often develop infections that seem unrelated to their injury. This article describes our experiences evaluating the contribution of head injury to infection rates as compared to severe trauma without head injury. We conclude that infection rates in patients with severe closed head injury are equivalent to similarly injured patients without head injury.

Rectal pH measurement in tracking cardiac performance in a hemorrhagic shock model.

OBJECTIVE AND DESIGN: We evaluated the utility of rectal mucosal pH measurement for tracking cardiac performance in hemorrhagic shock as compared with gastric tonometry. MATERIALS AND METHODS: Hemorrhagic shock was induced in five adult swine to a mean arterial pressure of 45-65 mm Hg. Hypotension was maintained for 30 minutes, resuscitation was accomplished with the shed blood and lactated Ringer's solution (3x blood volume). Gastric tonometry, rectal pH, and oxygen transport data were obtained at baseline, 0, and 30 minutes after onset of hypotension and after resuscitation. RESULTS: Intramucosal pH readings from gastric tonometry and rectal mucosal pH both showed a significant change from baseline to 0 and 30 minutes after onset of hypotension. Data after resuscitation were found to be statistically the same as baseline values. CONCLUSIONS: Rectal mucosal pH tracks cardiac performance as well as does gastric tonometry in hemorrhagic shock without as many limitations.

Load-independent left ventricular function in a hemorrhagic shock model.

Load-independent left ventricular (LV) function has been recently shown to be reversibly depressed in septic shock. The peak systolic pressure to end systolic volume ratio (PSP/ESV) is a load independent measure of LV function. We evaluated PSP/ESV in a porcine model of hemorrhagic shock. Hemorrhagic shock was induced in five adult swine by arterial bleeding to a mean arterial pressure of 45-65 mmHg. This hypotension was maintained for 30 min, and then each animal was resuscitated to baseline mean arterial pressure using shed blood and crystalloid solution. Data (echocardiographically derived ejection fraction and oxygen transport parameters) were collected at baseline, after 30 min of hypotension and postresuscitation. Although the cardiac index, a marker for systolic function, and the mean arterial pressure, as well as oxygen delivery and consumption returned to baseline levels, the PSP/ESV ratio remained low despite adequate fluid resuscitation. This model provides a reproducible hemodynamically stable cardiac dysfunction associated with hemorrhagic shock.