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Biomedical subjects

A C Berger

Publications and source records attributed to A C Berger.

33 records · Page 2Linked to original sources
PubMed1999

Heterogeneous gland size in sporadic multiple gland parathyroid hyperplasia.

BACKGROUND: The success rate for bilateral exploration in patients with primary hyperparathyroidism approaches 95%. Multiglandular parathyroid hyperplasia accounts for approximately 10% to 30% of primary hyperparathyroidism. The incidence of recurrent or persistent hyperparathyroidism is highest in familial forms of the disease, in which multiglandular disease is more common; this may be due to asymmetric enlargement of parathyroid glands. Because of improvements in tumor-imaging capability, some surgeons are now advocating unilateral exploration for primary hyperparathyroidism, but there is limited experience concerning how often these imaging methods fail. STUDY DESIGN: The outcomes of 7 patients who had sporadic primary hyperparathyroidism with multigland hyperplasia were reviewed. We gathered demographic data and laboratory values and reviewed radiologic tests, surgical findings, pathologic findings, and postoperative followup. RESULTS: All patients underwent preoperative localization with ultrasonography and technetium/sestamibi scans. The sensitivity of these two tests for the dominantly enlarged gland was 100% for both, but dropped to 0% and 5%, respectively, for all other enlarged glands. The sensitivity of CT and MRI for the dominant tumor was 67% (2 of 3) and 50% (1 of 2), respectively. Six of 7 patients underwent subtotal (3(1/2) gland) parathyroidectomy. The mean volume of all glands was 1.51+/-5.89 cm3 compared with a mean of 5.66+/-11.4 cm3 for all dominant glands and 0.123+/-0.1 cm3 for all nondominant hyperplastic glands. There was a large amount of variability between the volumes of dominant and other glands as demonstrated by large SDs from the mean. CONCLUSIONS: There is a marked heterogeneity in gland size in patients with sporadic multigland hyperplasia, which is similar to that found in multiple endocrine neoplasia type I. This heterogeneity may result in failure to recognize multigland disease if a unilateral neck exploration is performed. Intraoperative parathyroid hormone assay may prove to be an important adjunct in this population of patients who have unsuspected multigland disease.

Adult↗
PubMed1999

Isolated hepatic perfusion for lapine liver metastases: impact of hyperthermia on permeability of tumor neovasculature.

BACKGROUND: Hyperthermic isolated hepatic perfusion (IHP) has been shown to cause significant regression of advanced unresectable liver metastases in patients. Although there are different agents and treatment modalities used in IHP, the contribution of perfusion hyperthermia is unknown. PURPOSE: A large animal model of unresectable liver metastases and a technical standard for IHP in this model were established. This model was used to assess the effects of hyperthermia on vascular permeability of tumors and normal liver tissue during IHP. METHODS: Sixty-five New Zealand White rabbits were used in a series of experiments. Disseminated liver tumors were established by direct injection of 1 x 10(6) VX-2 cells into the portal vein by laparotomy in anesthetized animals. Several surgical perfusion techniques were explored to determine a reliable and reproducible IHP model. Vascular permeability in tumor versus liver was then assessed with Evan's Blue labeled bovine albumin under normothermic (tissue temperature 36.5 degrees C +/- 0.5 degree C), moderate hyperthermic (39 degrees C +/- 0.5 degree C), or severe hyperthermic (41 degrees C +/- 0.5 degree C) conditions. RESULTS: Tumor model and perfusion techniques were successfully established with inflow through the portal vein and outflow through an isolated segment of the inferior vena cava. A gravity driven perfusion circuit with stable perfusion parameters and complete vascular isolation was used. Vascular permeability was higher in tumor than in normal tissues (P = .03) at all time points during IHP. Hyperthermia resulted in a significant (up to 5-fold) increase in permeability of neovasculature; when severe hyperthermia was used, tumor vascular permeability was increased even more than normal liver permeability (P = .01). CONCLUSIONS: The VX-2/New Zealand White rabbit system can be used as a reproducible large-animal model for IHP of unresectable liver metastases. It can be used to characterize the contribution and mechanism of action of different treatment parameters used in IHP. Hyperthermia preferentially increases vascular permeability in tumors compared with liver tissue in a dose-dependent fashion, thus providing a mechanism for its presumed benefit during isolated organ perfusion.

Animals↗
PubMed1998

The clinical implications of hypophosphatemia following major hepatic resection or cryosurgery.

OBJECTIVES: To determine the incidence and predisposing factors leading to postoperative hypophosphatemia after major hepatic surgery and the consequences of this electrolyte abnormality. DESIGN: A retrospective study. SETTING: A university tertiary care referral center. PATIENTS AND METHODS: Thirty-five consecutive patients undergoing either major hepatic resections or cryosurgery from July 1994 through January 1997 were retrospectively reviewed for the occurrence of hypophosphatemia and postoperative complications. MAIN OUTCOME MEASURES: Prolonged ventilatory support, intensive care unit and hospital stays, and the incidence of postoperative complications. RESULTS: The overall incidence of hypophosphatemia in our series was 21 (67%) of 35 with a mortality rate of 1 (2.8%) in 35. Mean operative time, estimated blood loss, partial vascular occlusion time, and transfusion requirements were similar between the hypophosphatemic and the nonhypophosphatemic groups. The presence of postoperative complications was significantly greater in the hypophosphatemic group (17 [80%] of 21) vs the nonhypophosphatemic group (4 [28%] of 14) (P<.05). The incidence of antacid use in the hypophosphatemic group (14 [66%] of 21) was significantly higher than the use in the nonhypophosphatemic group (2 [14%] of 14) (P<.05). CONCLUSIONS: Hypophosphatemia commonly occurs in major hepatic procedures. The presence of moderate hypophosphatemia is associated with the use of antacid therapy but no other perioperative or operative variables. The occurrence of hypophosphatemia correlates with an increased incidence of postoperative complications. Awareness of this entity can direct aggressive replacement of phosphates and avert the occurrence of severe hypophosphatemia and associated complications.

Adult↗
PubMed1998

Genetically modified fibroblasts induce angiogenesis in the rat epigastric island flap.

METHODS: Gene therapy was tested for inducing functional angiogenesis in the superficial rat epigastric island flap to allow earlier pedicle division. Autologous rat fibroblasts were grown, harvested, cultured and retrovirally transfected to produce platelet-derived growth factor AA (PDGF-AA), an angiogenetically active protein. Stable gene expression was monitored by PDGF-AA enzyme-linked immunosorbent assay (ELISA). One hundred and eighty animals were divided into three groups (I-III) and a bilateral flap created in each animal. In all experiments, the right-sided flap was subjected to experimental treatment and the left-sided flap served as control (1ml saline 0.9%). During flap elevation, group I received 5X10(6) GMFB (genetically modified fibroblasts) plus 1 ml Dulbecco's modified Eagle's medium. Group II was treated with 5x10(6) NMFB (non-modified fibroblasts) plus 1 ml medium and group III received 1 ml medium only. The flaps were sutured back and the vascular pedicle was bilaterally ligated and divided in each of ten animals during the following 6 days. After 7 days, the flaps were harvested, the amount of necrosis measured and histologically examined. RESULTS: The GMFB produced up to 560 times more PDGF-AA than the NMFB, measured by ELISA. The GMFB-treated flaps tolerated surgical division of the vascular pedicle significantly earlier than groups II and III. Histologically, fibroblasts persisted in all flaps of groups I and II, without major inflammatory reaction. In all GMFB-treated flaps, massive angiogenesis could be demonstrated. CONCLUSION: By means of retroviral gene transfer, autologous rat fibroblasts can be genetically modified for stable expression of the PDGF-A gene to produce high amounts of PDGF-AA, which is angiogenetically active. After injection into the panniculus carnosus, these cells induce functional angiogenesis to permit earlier division of the vascular pedicle in this flap model.

Animals↗
PubMed1998

[Functional angiogenesis induction in epigastric islet flap rat model after genetic modification of fibroblasts].

Gene therapy was tested for inducing functional angiogenesis in the superficial rat epigastric island flap to allow earlier pedicle division. Autologous rat fibroblasts were grown, harvested, cultured and retrovirally transfected to produce PDGF-AA, an angiogenetically active protein. Stable gene expression was monitored by PDGF-AA ELISA. 180 animals were divided into 3 groups (I-III) and a bilateral flap created in each animal. In all experiments, the rightsided flap was subjected to experimental treatment and the left-sided flap served as control (1 ml saline 0.9%). During flap elevation, group I received 5 x 10(6) GMFB (genetically modified fibroblasts) plus 1 ml DMEM as medium. Group II was treated with 5 x 10(6) NMFB (non modified fibroblasts) plus 1 ml medium and group III received 1 ml medium alone. The flaps were sutured back and the vascular pedicle was bilaterally ligated and divided in each 10 animals during the following 6 days. 7 days later, the flaps were harvested, the amount of necrosis measured and histologically examined. The GMFB produced up the 560-times more PDGF-AA than the NMFB, measured by ELISA. The GMFB-treated flaps tolerated surgical division of the vascular pedicle significantly earlier than groups II and III. Histologically, fibroblasts persisted in all flaps of groups I and II without major inflammatory reaction. In all GMFB-treated flaps, massive angiogenesis could be demonstrated. By means of retroviral gene transfer autologous rat fibroblasts can be genetically modified for stable expression of the PDGF-A gene to produce high amounts of PDGF-AA, which is angiogenetically active. After injection into the panniculus carnosus, these cells induce functional angiogenesis to permit earlier division of the vascular pedicle in this flap model.

Animals↗
PubMed1997

[Early microsurgical revision of the brachial plexus in traumatic birth injuries. Patient selection and outcome].

A review of the literature reveals that with conventional treatment alone or in combination with secondary muscle/tendon transfer, about 4-43% of cases show incomplete recovery with severe functional and/or aesthetic impairment (group III). If these patients undergo early microsurgical brachial plexus revision, regeneration without significant functional and/or aesthetic impairment (shift from group III to group II) can be achieved in 80-90% of cases. Moreover, microsurgical reconstruction of the brachial plexus increases the possibilities of secondary muscle/tendon transfers. Therefore, provided patient selection is good, severe obstetrical brachial plexus injuries should be scheduled for early microsurgical revision. There is no need to wait for a frustrating spontaneous recovery. Our concept is based on our experience with more than 1100 patients presenting with brachial plexus lesions between 1981 and 1996 and treated in our institution. There were 217 obstetrical brachial plexus lesions, 133 of which were treated conservatively. In 84 cases operative treatment was necessary. Fifty-one cases underwent early revision of the brachial plexus, and secondary tendon transfer was done in 33 patients.

Adolescent↗
PubMed1995

Decision making and results in subtotal and total lower leg amputations: reconstruction versus amputation.

As a result of modern therapeutic and technological advances, the surgeon has the ability to salvage even the most severely injured lower limbs. However, the success of replantation nowadays is no longer measured simply on the basis of restoration of viability but also on functional outcome compared with primary amputation with early prosthetic fitting, the risk to the patient during and after replantation and the overall time of treatment which should not exceed 2 years. Although every major limb replantation has to be considered individually, the decision-making process for reconstruction (replantation/revascularisation) versus amputation with subsequent early prosthetic fitting should be determined by objective criteria. Based on personal experience and an extensive literature search, an algorithm for treatment of amputation or amputation-like injuries to the lower leg has been developed and tested in a clinical study. A 100% viability success rate was achieved. There was not only a significant increase in the percentage of "functional extremities" but also a doubling in grade I results. Moreover, there was a 50% reduction in patients presenting a "non-functional extremity", and no patient required a secondary re-amputation. The replantation risk (e.g., risk of severe systemic disturbance during and/or after replantation) was about 16.6% (2/12) in our study. There was a significant decrease in the postoperative complication rate and no patient died during or after replantation. Based on our experience, if reconstruction in subtotal or total lower leg amputation is done for a well-selected patient group, good functional results with a reasonable replantation risk and a reasonable time for social re-integration can be achieved.

Adult↗
PubMed1994

Afferent arteriovenous anastomosis for thumb replantation: a case report.

Described is a case where an afferent arteriovenous anastomosis was successfully employed in the replantation of a large piece of composite tissue amputated from a patient's thumb. The operative procedure is described and aspects of arterialized venous vascular networks are discussed.

Anastomosis, Surgical↗
PubMed1993

Do-not-resuscitate orders in a children's hospital.

OBJECTIVES: a) To quantify the use of do-not-resuscitate orders in a tertiary care children's hospital; and b) to characterize the circumstances in which such orders are written. DESIGN: Retrospective chart review. SETTING: University teaching hospital. PATIENTS: All inpatients who died in an urban children's hospital over a 1-yr period of time. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The hospital records of 54 of 69 patients who died were reviewed. Eighty-two percent of patient deaths occurred in the ICU; 13% of patient deaths occurred in the operating room, and 5% occurred in a medical ward. Other findings included the following: 25 (46%) of 54 patients died after attempted cardiopulmonary resuscitation; 13 (24%) patients were brain dead; and 16 (30%) died with a do-not-resuscitate order in effect. Age was associated with resuscitation status: do-not-resuscitate orders were written for five (21%) of 22 infants (< 1 yr of age); seven (50%) of 14 children (1 to 11 yrs of age); and four (80%) of five adolescents who died (p < .002). Fifteen of 16 do-not-resuscitate orders were written for patients who were in the ICU, where they remained until death. Findings in patients when the do-not-resuscitate orders were written were as follows: 15 ICU patients were receiving mechanical ventilation; 14 (95%) of 15 were receiving inotropic agents; 12 (80%) of 15 patients were receiving narcotic analgesics; and one (6%) patient was being dialyzed. At least one therapeutic modality was withdrawn in 7 (44%) of 16 patients. Do-not-resuscitate orders followed documented conferences with physicians and family members in 13 (81%) of 16 cases. These discussions were initiated by physicians in 12 (92%) of 13 cases. CONCLUSIONS: Do-not-resuscitate orders in pediatric patients are written more often in older than younger hospitalized children who die. Most do-not-resuscitate orders are written for patients who are receiving aggressive medical therapy in the ICU.

Age Factors↗
PubMed1992

Noninvasive vascular studies: a comparison with arteriography and surgical findings in the upper extremity.

Noninvasive vascular studies of the upper extremity were compared with the accepted standards of arteriography and surgical exploration. Results of noninvasive vascular studies and 40 arteriograms in 37 patients revealed agreement in 95% of the cases. Further comparison between results of noninvasive studies and surgical findings in 17 patients revealed a correlation of 100%. Thus, findings from our noninvasive vascular studies agreed with arteriographic and surgical findings with respect to the type, location, and extent of disease in 97% of patients studied. We conclude that noninvasive studies of the upper extremity are accurate, safe, reproducible, inexpensive, and well tolerated by patients. Noninvasive vascular studies also provide information on vascular dynamics that is not available from routine arteriography.

Adolescent↗
PubMed1991

Replantation.

Explore the source record for details and available documents.

Amputation, Traumatic↗
PubMed1986

Abnormalities of the in vitro cellular and humoral responses to tetanus and influenza antigens with concomitant numerical alterations in lymphocyte subsets in Down syndrome (trisomy 21).

Peripheral blood leukocytes (PBL) from noninstitutionalized individuals with trisomy 21, paired with closely age-matched and/or family members as controls, were analyzed for different aspects of their cellular and humoral immune responses, and were phenotypically characterized by means of various monoclonal antibodies. Both the in vitro PBL proliferative and antibody responses to a bacterial antigen (tetanus toxoid) and to viral antigens (influenza A/Bangkok and B/Singapore) were significantly decreased in trisomy 21. In addition, bacterial and viral antigen-induced in vitro interleukin 2 (IL 2) production was markedly reduced, although mitogen (PHA)-stimulated IL 2 production was not impaired. The functional abnormalities observed in trisomy 21 PBL occur concomitantly with numerical alterations in circulating lymphocyte subsets in these same individuals. Although no difference was observed between the trisomic and control groups in the percentage of total T and B lymphocytes, a decreased level of Leu-3a + 3b-positive cells (T helper/inducer cells) and an increased level of Leu-2a-positive cells (T suppressor/cytotoxic cells) that co-expressed Leu-15 (suppressor alone) were noted.

Adolescent↗
PubMed1981

Power spectrum analysis of heart rate fluctuation: a quantitative probe of beat-to-beat cardiovascular control.

Power spectrum analysis of heart rate fluctuations provides a quantitative noninvasive means of assessing the functioning of the short-term cardiovascular control systems. We show that sympathetic and parasympathetic nervous activity make frequency-specific contributions to the heart rate power spectrum, and that renin-angiotensin system activity strongly modulates the amplitude of the spectral peak located at 0.04 hertz. Our data therefore provide evidence that the renin-angiotensin system plays a significant role in short-term cardiovascular control in the time scale of seconds to minutes.

Angiotensins↗
PubMedDate not supplied

Endothelial monocyte-activating polypeptide II, a tumor-derived cytokine that plays an important role in inflammation, apoptosis, and angiogenesis.

The interactions between a tumor and its surrounding environment are complex and characterized by a variety of factors. Tumors produce a number of proteins that enable them to recruit a vascular supply, invade into surrounding tissues, and metastasize to distant sites. The host, in turn, responds to these signals by producing its own repertoire of molecules that may either assist or prevent the actions of the tumor. A thorough understanding of this relationship is critical to the development of novel anti-cancer therapies. The tumor-derived cytokine endothelial monocyte-activating polypeptide II (EMAP-II) has profound effects on the tumor as well as on host response. These effects target the inflammatory cascade as well as the processes involved in angiogenesis. In this review the authors describe the current understanding of the role of EMAP-II in inflammation, apoptosis, and angiogenesis and use this molecule to illustrate the complex interactions that occur in the tumor microenvironment.

Angiogenesis Inhibitors↗