Biomedical subjects
Publications and source records attributed to D J Martin.
Primary splenic pregnancy is the rarest form of extrauterine pregnancy. Only six cases have previously been documented, none of which occurred in North America. A case of this rare entity is presented in which a pregnancy was found to arise from the spleen, requiring splenectomy. In addition to the classic signs of a fulminant ruptured ectopic pregnancy, a history of upper abdominal pain was the only distinguishing feature.
Class II actin genes usually specify a polypeptide with a Met-Cys-Asp NH2 terminus, whereas the actin itself begins with an acetyl (Ac)-Asp(Glu). Previous studies with Drosophila actin showed that the first detectable intermediate is one with an Ac-Cys NH2 terminus which is subsequently cleaved in a novel reaction to expose the Asp. The initiator Met was probably removed early in translation as a free amino acid. To determine whether the class II actin initiating Met could also be removed in an acetylation-dependent manner, we translated Drosophila mRNA in a rabbit reticulocyte lysate in which protein acetylation was inhibited. After 60 min, three actin intermediates were detected, NH2-Met-Cys-Asp-actin, Ac-Met-Cys-Asp-actin, and NH2-Cys-Asp-actin. During processing in the presence of acetyl-CoA, three additional species were observed with NH2-terminal Ac-Cys-Asp, NH2-Asp, and Ac-Asp segments. In a time- and acetyl-CoA-dependent fashion, Met-Cys-Asp-actin was processed to the mature actin, presumably through an Ac-Met-Cys-Asp intermediate. Thus, two different pathways for removal of the initiator Met of class II actins, acetylation-dependent and independent, are possible. Since no class II actin intermediate containing the initiator Met is seen in vivo, although in class I actins this intermediate is observed, the most probable pathway for class II actins in vivo is the cotranslational removal of the initiator Met as a free amino acid.
In order to ascertain the extent of hypothalamo--pituitary--thyroid (HPT) axis dysfunction in endogenous depression, we determined nocturnal serum thyrotropin (TSH) concentrations, TSH responses to thyrotropin releasing hormone (TRH) administration, and serum triiodothyronine (T3) and thyroxine (T4) concentrations in 40 Research Diagnostic Criteria primary, definite endogenous depressives and 40 individually matched normal control subjects. We also examined the relationships of the HPT measures to pre- and post-dexamethasone (DEX) serum and urine cortisol measures and, in the patients, to subject characteristics, the diagnosis of endogenous/melancholic depression by different systems, and the overall severity and specific dimensions of depressive symptomatology. Compared to their matched controls, the patients showed significant reductions in nocturnal serum TSH and serum T3 concentrations. Neither the TSH responses to TRH nor serum T4 concentrations were significantly different between the two groups of subjects. In the patients, none of the subject characteristics, diagnostic schemes for endogenous/melancholic depression or specific aspects of depressive symptomatology were significantly related to HPT activity. The measures of HPT activity were unrelated to measures of hypothalamo--pituitary--adrenal cortical (HPA) axis activity in both groups of subjects.
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In order to ascertain the extent of hypothalamo-pituitary-adrenal cortical (HPA) hyperactivity in endogenous depression, we determined circadian serum cortisol patterns, cortisol responses to dexamethasone (DEX) administration, and urine free cortisol excretion before and after DEX administration in 40 definite endogenous depressives diagnosed with the Research Diagnostic Criteria. The cortisol measures ranged from normal to clearly elevated. To elucidate the clinical correlates of these hormone measures in the patients, we examined the relationships of the pre- and post-DEX cortisol measures to the diagnosis of endogenous/melancholic depression by different systems and to the overall severity and specific dimensions of depressive symptomatology. In this group of endogenous depressives, none of the diagnostic schemes for endogenous/melancholic depression which we studied was significantly related to the pre- or post-DEX cortisol measures. Of the other subject and symptom variables, only age and the agitation/anxiety factor of the Hamilton depression scale shown consistent relationships with the cortisol measures. Both were positively correlated, to a moderate degree, with the hormone measures, and they were not correlated with each other. Together they explained approximately 20% of the variance in the cortisol measures. Thus, within a group of moderately to severely ill endogenous depressives, the older and the more agitated anxious patients have a significantly greater likelihood of showing increased HPA activity. These findings indicate that age should be controlled in studies of the HPA axis and that the subjective experience of anxiety may contribute to HPA hyperactivity in endogenous depression.
An institutionwide commitment is necessary for the success of a liver transplantation program. Although the number of people available to manage anesthesia for such surgery may vary, a minimally staffed transplantation team must include a staff anesthesiologist, an anesthesia resident, one or two certified nurse-anesthetists, and a nonprofessional to obtain and run specimens to the laboratory and blood bank; the operating room must be connected by intercom and telephone to support services. Another technician may be present to collect specimens and data for research purposes. Additional staff anesthesiologists, certified nurse-anesthetists, and anesthesia residents should be on call for other emergency surgery. The staff of laboratory and blood bank facilities must participate wholeheartedly to meet ongoing requirements during a liver transplantation. Enormous quantities of packed red cells (up to 250 units), fresh-frozen plasma, platelets, and occasionally cryoprecipitate must be immediately available. In addition, the donor pool and the supply of on-hand blood must be large enough to prevent shortages of blood for other emergency or routine surgery. Liver transplantation procedures last an average of 12 hours and cannot easily be accommodated in a busy operating room schedule. It is not reasonable to expect other patients, other surgeons, the anesthesiology department, and the hospital to postpone routine or other emergency surgery while a liver transplantation is being performed. Thus, the hospital must provide facilities to accommodate such a program either by new construction or by remodeling or reassigning operating space.
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The adverse effects of albumin resuscitation on coagulation activity, cardiopulmonary function, and extravascular flux of nonalbumin protein have made fresh-frozen plasma (FFP) an attractive alternate volume expander for hemorrhagic shock. This study addresses the effects of FFP on cardiopulmonary hemodynamics and protein flux. Whole blood was collected three and six weeks before shock, separated into red blood cells (PRBCs) and FFP, and stored. In 24 conditioned splenectomized dogs, resuscitation from reservoir shock of two hours' duration consisted of autologous PRBCs and balanced electrolyte solution (BES) in control dogs and PRBCs, BES, and FFP in plasma-treated dogs. Hemorrhagic shock reduced serum albumin and IgG levels in both groups. Resuscitation with FFP led to a higher cardiac output, left ventricular stroke work (LVSW), and pulmonary capillary wedge pressure (PCWP). The PCWP/LVSW ratio was comparable for both groups. Postshock day 2 serum albumin and IgG levels and lymphatic albumin and IgG concentrations were increased in plasma dogs. Therefore, FFP supplement to PRBC and BES resuscitation does not derange the PCWP/LVSW ratio or reduce intravascular nonalbumin proteins.
We report a case of choroid plexus papilloma arising from the right lateral ventricle in a 4-month-old infant. Because of intermittent vomiting, abdominal pain, and diarrhea, the child was initially treated with intravenous rehydration, which aggravated the symptoms, and a bulging fontanel developed. Before a planned lumbar puncture, cranial ultrasound was performed, which disclosed a choroid plexus papilloma. The tumor was removed surgically, and the child made an uneventful recovery. We discuss the diagnostic value of cranial ultrasound compared to computed tomographic (CT) scan and angiography.
Prospective sonographic evaluation after water ingestion in 25 normal children aged 2 days to 15 years (mean 6.3 years) demonstrated that normal gastric wall thickness was less than 3 mm. Gastric walls of 5-15 mm thickness were seen in nine of about 6500 children undergoing abdominal sonographic examinations. These nine patients had a variety of unusual diseases, including varioliform gastritis, gastric ulcer, lymphoid hyperplasia, and gastric hamartoma. Previously unreported sonographic appearances were seen. The sonographic examination was instrumental in the detection of five clinically unsuspected gastric lesions and helpful in follow-up in four others.
Acanthamoeba actin is the only actin sequenced to date that has neither an NH2-terminal Ac-Asp nor Ac-Glu residue. The protein begins with an Ac-Gly-Asp and is coded for by a gene that specifies a polypeptide beginning Met-Gly-Asp. Thus, the Acanthamoeba actin gene would appear to specify a class II actin with the usual NH2-terminal Cys replaced with a Gly. Previous studies (Rubenstein, P. A., and Martin, D. J. (1983) J. Biol. Chem. 258, 11354-11360) revealed that for class II actins the Met is probably removed early in translation and the Cys is removed post-translationally as an Ac-Cys residue. Two possibilities might explain why Acanthamoeba actin is not processed in a similar fashion. Either Ac-Gly is not a substrate for the enzyme or the enzyme is absent from the organism. To test these alternatives, Acanthamoeba actin was labeled in vivo with [35S]methionine and incubated with processing enzyme from rat liver, rabbit reticulocytes, and Dictyostelium. In no case did the processing reaction occur, indicating that Ac-Gly is not recognized by the enzyme as a substrate. Furthermore, we could not reproducibly detect the presence of a processing enzyme in Acanthamoeba. We were, however, able to show the presence of such an enzyme in Dictyostelium, the first demonstration of this activity in a lower eukaryote.
Between 1919 and 1981, 16 children with primary cardiac tumors (8 rhabdomyomas, 5 fibromas, 2 myxomas, and 1 rhabdomyosarcoma) and 59 children with secondary tumors of the cardiovascular system were seen at The Hospital for Sick Children in Toronto. Distant metastases in 45 children of the latter group, in descending order of frequency, were from non-Hodgkin's lymphoma, neuroblastoma, soft tissue and bone sarcoma, Wilms' tumor, and hepatoma, and involved the myocardium and pericardium. In the remaining 14 children, tumor thrombi from Wilms' tumor (9 cases), adrenal (2 cases) and hepatocellular carcinoma (2 cases), and endodermal sinus tumor (1 case) extended directly into the great veins and/or cardiac chambers. Children with primary and secondary tumors often present with nonspecific clinical, plain radiographic, electrocardiographic, and M-mode echocardiographic findings. Early recognition, utilizing special diagnostic procedures such as two-dimensional echocardiography, computerized axial tomography, angiocardiography, and inferior venocavography, followed by elective surgical resection of tumor under cardiopulmonary bypass and/or radiation and chemotherapy, offers patients with cardiovascular tumors the best chance of cure.
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In order to simplify the dexamethasone suppression test (DST), we have administered a lower dosage of dexamethasone (DEX) and shortened the sampling time to a single morning blood sample. DEX (in dosage increments from 0.125 to 1.0 mg, p.o.) was administered at 2300 h to normal volunteers in a double-blind randomized fashion, and blood samples were taken at 0700 h the following morning. While significant cortisol suppression occurred after the 0.375 mg, 0.5 mg, and 1.0 mg doses of DEX, the 0.5 mg dose was the smallest that clearly suppressed cortisol in all eight subjects. This dose then was used to test the feedback sensitivity of the central nervous system (CNS)-pituitary-adrenal axis in endogenously depressed patients. Twenty endogenously depressed patients and 20 normal volunteers were given both the standard 1.0 mg DST, with post-DEX serum cortisol determined at 1500 h, and the simplified 0.5 mg DST, with post-DEX serum cortisol determined at 0700 h. Four patients (20%) and one control (5%) were nonsuppressors after the 1.0 mg DST, and nine patients (45%) and one control (5%) were nonsuppressors after the 0.5 mg DST. In addition, nine patients with major depression (nonendogenous subtype) and 15 patients with panic attacks also were studied using the 0.5 mg DST. Only 2 of these 24 patients (8%) were nonsuppressors. The results suggest that the single-sample 0.5 mg DST is more sensitive than the standard 1.0 mg DST, and the specificity of the modified test appears comparable to the standard form of the test.
Venous bypass restores normal hemodynamic physiology during the critical anhepatic phase of orthotopic transplantation of the liver. Its routine use in adults undergoing transplantation in Pittsburgh has resulted in lower operative blood losses, a lower frequency of postoperative renal failure, and a greater probability of survival for all but the highest risk patients. Because it allows for a longer anhepatic phase, the surgeon has the option of tailoring the native hepatectomy to the needs of the individual case, even to the point, in difficult cases, of obtaining most of the hemostasis after removal of the native liver, but before sewing in the donor organ. Selective use of bypass in children may offer similar advantages.
The efficacy of supplemental fresh frozen plasma (FFP) therapy after massive packed red cell (PRBC) replacement for hemorrhagic shock was studied in 22 conditioned dogs. Ten dogs were randomized to received FFP, balanced electrolyte solution (BES), and PRBC, while 12 dogs received BES and PRBC. Coagulation factor activity for Factors I, II, V, VII and VIII, as well as antithrombin III (AT III), prothrombin time, partial thromboplastin time, and thrombin time, were measured at preshock, postshock, postresuscitation, and postshock day two. All coagulation factor activities fell with shock and decreased further with resuscitation in both groups. Factor II (a procoagulant) and AT III (an anticoagulant) fell significantly less after resuscitation in the plasma dogs; otherwise, no postresuscitation differences were seen. The changes in factor activity from postresuscitation until day two reflected factor half life and molecular weight, independent of FFP therapy. These data show that prophylactic FFP therapy does not efficiently restore coagulation activity. Consequently, routine FFP therapy for its procoagulant effects after hemorrhagic shock should be abandoned pending controlled studies in man.
Prior studies have suggested that male patients with uremia suffer from sexual dysfunction that worsens when they are placed on maintenance hemodialysis. The authors report a prospective study of the effect of maintenance hemodialysis on male sexual functioning using nocturnal penile tumescence (NPT) measures and detailed sexual histories. Twenty men already on maintenance hemodialysis and 23 men with advanced renal failure who began maintenance hemodialysis within 4 months of entering the study were followed at 4-month intervals for 1-year and 6-month intervals for the following 18 months. Sexual performance as assessed by NPT, frequency of intercourse, and complaints of erectile failure remained remarkably stable over time for both groups. When renal failure patients moved to maintenance hemodialysis, their frequency of intercourse increased significantly despite stability of NPT. These results suggest not only that maintenance hemodialysis does not worsen sexual functioning, but that adaptation to a sexual deficit is possible after starting hemodialysis.
This article discusses a large number of neonatal conditions for which ultrasound, by virtue of its noninvasiveness and its minimum of disturbance to the neonate, is the ideal mode for first investigation.