Long gamma-ray bursts and core-collapse supernovae have different environments.

When massive stars exhaust their fuel, they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even more brilliant relativistic explosion known as a long-duration gamma-ray burst. One would then expect that these long gamma-ray bursts and core-collapse supernovae should be found in similar galactic environments. Here we show that this expectation is wrong. We find that the gamma-ray bursts are far more concentrated in the very brightest regions of their host galaxies than are the core-collapse supernovae. Furthermore, the host galaxies of the long gamma-ray bursts are significantly fainter and more irregular than the hosts of the core-collapse supernovae. Together these results suggest that long-duration gamma-ray bursts are associated with the most extremely massive stars and may be restricted to galaxies of limited chemical evolution. Our results directly imply that long gamma-ray bursts are relatively rare in galaxies such as our own Milky Way.

Decay of the GRB 990123 optical afterglow: implications for the fireball model

Broad-band (ultraviolet to near-infrared) observations of the intense gamma ray burst GRB 990123 started approximately 8.5 hours after the event and continued until 18 February 1999. When combined with other data, in particular from the Robotic Telescope and Transient Source Experiment (ROTSE) and the Hubble Space Telescope (HST), evidence emerges for a smoothly declining light curve, suggesting some color dependence that could be related to a cooling break passing the ultraviolet-optical band at about 1 day after the high-energy event. The steeper decline rate seen after 1.5 to 2 days may be evidence for a collimated jet pointing toward the observer.

The role of preoperative factor V Leiden screening in different geographic populations.

Patients harboring a specific mutation in the coagulation factor V gene have been identified as being at significantly increased risk for venous thrombosis. A simple genetic test that identifies carriers of this mutation (the factor V Leiden allele) is available and may have utility in various clinical settings, including preoperative risk assessment for thromboembolic complications. In this regard, it is generally agreed that prospective studies addressing the role of preoperative factor V Leiden mutational analysis are needed to clearly define the clinical prognostic/diagnostic significance of the presence of this mutation in surgical patients. This report questions the role that population dynamics (genetic and environmental backgrounds of individual populations) plays in the analysis of factor V genotypic data in relation to postsurgical thromboembolic complications. We have determined that the frequency of individuals carrying the factor V Leiden allele is 7.9 per cent for our South Central Pennsylvania population (395 wild type, 32 heterozygotes, 2 homozygotes) using a polymerase chain reaction-restriction fragment length polymorphism technique that specifically detects the factor V Leiden mutation. This baseline population information is useful from both a clinical and a basic science viewpoint. However, considering the various unknown genetic and environmental differences between geographically distinct populations, the significance of this result, in terms of clinical management of our surgical patients, is yet to be determined.

Obturator hernia needs a laparotomy, not a diagnosis.

The obturator hernia is rare, accounting for only 0.05% of all hernias and 0.2% of all small-bowel obstructions requiring laparotomy at our institution. Typically, there is a delay in diagnosis and surgical intervention, despite the presence of a bowel obstruction. A laparotomy is needed, not a preoperative diagnosis.

First place winner of the Conrad Jobst Award in the gold medal paper competition. Nitric oxide synthase inhibitors N-monomethylarginine and aminoguanidine prevent the progressive and severe hypotension associated with a rat model of pancreatitis.

The objective of this study was to determine whether the observed vascular collapse and other pathologic features of severe pancreatitis may be related to the induction of nitric oxide synthase (NOS). The rat model of pancreatitis reported by Schmidt et al. was employed. Rats in the experimental groups received pretreatment with known NOS inhibitors, N-Monomethylarginine (NMMA) or Aminoguanidine (AG). Controls included sham-operated rats without pancreatic insult and a diseased control group which received pretreatment with normal saline (NS). Arterial blood pressure was continuously recorded with a femoral arterial catheter connected to a transducer and monitor. Fluid resuscitation for hypotension followed a strict protocol with the administration of 5.0 cc NS for sustained decreases in systolic blood pressure (SBP) below 90 mm Hg at 5-minute intervals. Laboratory parameters and histopathology confirmed the induction of pancreatitis, with 6 to 15-fold increases in serum amylase levels and an average of approximately 20% decrease in serum ionized Ca++ levels. Immunohistochemical studies of the pancreas revealed that pancreatic insult resulted in the induction of NOS. Rats in the saline control group (n = 5) became hypotensive (SBP less than 90 mm Hg) between 3 and 4 hours post pancreatic insult and required an average of 110.0 cc (3-4 x blood volume) of NS fluid resuscitation. Rats which were not resuscitated (n = 5) did not survive.(ABSTRACT TRUNCATED AT 250 WORDS)

3D CT reconstruction in the surgical management of hepatic injuries.

We employed 3D reconstruction of CT images for evaluation of hepatic injuries in a series of eight trauma patients. One had additional reconstruction of a renal injury. 3D imaging provided precise anatomical delineation of damaged areas, particularly in relation to major vessels. Moreover, the imaging agreed with operative findings in every case. The 3D reconstruction facilitated decisions regarding intraoperative, reoperative and non-operative management. The improved imaging provided by 3D reconstruction may allow hepatic CT scans to be interpreted with greater ease and accuracy than conventional CT. We believe this is the first report of its use in liver trauma. Current indications may include postoperative confirmation of the extent of hepatic injuries, assessment before reoperation, and contribution to decisions regarding non-operative management. A limitation at present is the time taken for image production, but we suggest that in the future 3D imaging might contribute to evaluation before emergency surgery in patients with abdominal injuries.

Five-year survival of 100 women with carcinoma of the breast diagnosed by screening mammography and needle-localization biopsy.

Carcinoma of the breast was studied in 100 women who underwent needle localization and open breast biopsy for lesions found by screening mammography from January 1980 to May 1987. The average age of the patients found to have carcinoma was 59.2 years, and 16 percent of patients were younger than 50 years of age. Pathologic examination revealed 62 patients with infiltrating ductal carcinoma, 31 patients with ductal carcinoma in situ, and seven patients with infiltrating lobular carcinoma. In 34 patients the carcinoma was microscopic. Thirty-six patients had carcinomas less than or equal to 1 centimeter, and 30 patients had carcinomas greater than 1 centimeter. Eighty-four patients were treated with total mastectomy and axillary dissection. Seven patients were treated with wide excision, axillary dissection and radiation therapy. Nine patients underwent lesser treatments. Among the 91 patients undergoing axillary dissection, 82 were node negative, eight had one to three positive nodes, and one had four or more positive nodes. One hundred percent of patients with ductal carcinoma in situ who underwent axillary dissections (24 of 31) were node negative. Only two patients received adjuvant hormonal therapy, and one woman received adjuvant chemotherapy. All patients were under observation for at least five years or to the time of death (mean follow-up period, 5.8 years). Of the 100 patients with complete follow-up, 92 are alive and disease free. Four patients with carcinoma that metastasized have died. Three patients are alive with known recurrence. One patient died of other causes six months after carcinoma was diagnosed. Widespread use of screening mammography coupled with judicious use of needle-localization biopsy will lead to the early diagnosis of carcinoma of the breast. Such early diagnosis of carcinoma does lead to an excellent (95 percent) five-year survival rate.

Mammographically detected carcinoma of the breast.

A ten year experience with 2,077 consecutive mammographically guided needle-localization biopsies at a large community hospital is presented. By using this technique, 13.8 per cent of the biopsies were positive, yielding 284 carcinomas. The nonpalpable carcinomas discovered by mammography and the needle-localization technique were compared with those palpable carcinomas diagnosed during the same time period at York Hospital. In the final year of the study, 42.1 per cent of carcinomas treated at the York Hospital were diagnosed by the needle-localization technique. The mammographically detected carcinomas were smaller, more often node-negative and found, on average, at an earlier patient age than palpable carcinomas. The results of this study demonstrate that screening mammography, coupled with an aggressive biopsy policy, will lead to the discovery of many early, node-negative carcinomas of the breast.

Neuroleptic malignant syndrome in a trauma patient: case report.

Presented is a case report of a multiple trauma patient whose post-traumatic course was complicated by neuroleptic malignant syndrome triggered by therapeutic haloperidol treatments. Once the syndrome was recognized and treated, a dramatic recovery was achieved.