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Biomedical subjects

V K Rao

Publications and source records attributed to V K Rao.

At least 19 recordsLinked to original sources
PubMed1992

Removal of venous endothelium with air.

Much research on the activity and half-life of endothelium-derived substances has entailed the removal of endothelium from arteries by mechanical or enzymatic processes. It has been observed that the technique used for the removal of arterial endothelium may profoundly affect smooth muscle function and release of prostanoids by the vessel wall. The function and patterns of regeneration of arterial endothelium have been extensively described, but there is a relative paucity of information about the venous endothelium, due in part to the difficulty of its removal. We developed a technique for removal of the endothelium of rabbit femoral veins by passing a stream of air through the lumen of the vessel to dry and remove the endothelium. The effectiveness of endothelium removal was verified by the lack of in vitro reactivity to endothelium-dependent relaxing substances, examination of frozen sections of vessels, labeled with fluorescent-tagged acetylated low-density lipoprotein, with fluorescent light microscopy and scanning electron microscopy of vessel segments. Air drying effectively removed the endothelium and abolished mechanical responses to endothelium-dependent vasodilators but did not affect the function of the smooth muscle. We propose the use of air to remove endothelium from veins to be used to study endothelium-derived factors since this method achieves complete removal of endothelium without causing detectable damage (morphological or functional) to the remainder of the vessel wall.

Air↗
PubMed1992

Angiomatosis of soft tissue. An analysis of the histologic features and clinical outcome in 51 cases.

The clinicopathologic features and clinical behavior of 51 cases of angiomatosis of soft tissue are analyzed. We have defined this lesion as a histologically benign vascular lesion that affects a large segment of the body in a contiguous fashion either by vertically involving multiple tissue types (e.g., subcutis, muscle, bone) or by involving similar tissue types (e.g., multiple muscles). Such lesions usually present in the first two decades of life and have a highly characteristic but not totally specific histologic pattern. The common pattern consists of a haphazard proliferation of vessels of varying sizes, particularly large veins. The latter have irregularly attenuated walls and intimal redundancies. However, the most distinctive feature is the presence of clusters of capillary vessels residing within or just adjacent to the vein walls. A second but uncommon pattern is that of clusters of capillary-sized vessels infiltrating the soft tissues. Both types are typically associated with large amounts of fat, suggesting that these lesions are more generalized mesenchymal proliferations rather than exclusive vascular lesions. This idea is supported by one unique case that included as part of the lesion a diffuse proliferation of glomus cells. Follow-up information in 25 cases (median 5 years; range 1-24) indicated that 22 patients experienced local recurrences. Nine patients developed more than one recurrence. There was no correlation between the age of onset of the lesion and the number of recurrences.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Well-differentiated liposarcoma (atypical lipoma) of deep soft tissue of the extremities, retroperitoneum, and miscellaneous sites. A follow-up study of 92 cases with analysis of the incidence of "dedifferentiation".

Ninety-two cases of well-differentiated liposarcoma of deep soft tissue of the extremity, retroperitoneum, and groin with follow-up information of at least 2 years and no evidence of dedifferentiation at the time of diagnosis were studied to determine their long-term behavior. The tumors occurred most commonly in the muscles of the extremity (46 cases), followed by the retroperitoneum (23 cases), groin (14 cases), and miscellaneous sites (nine cases). Tumors in the retroperitoneum recurred in nearly all cases (21 of 23 cases), occasionally caused patient death, and dedifferentiated in four cases (median time to dedifferentiation, 8 years). Tumors in the groin had a similar high recurrence rate (11 of 14 cases), caused death of patients (two of 14 cases), and dedifferentiated (four of 14 cases). In contrast, those in the extremity recurred less frequently (20 of 46 cases) and had no disease-related mortality. Three of 46, however, underwent dedifferentiation (median time to dedifferentiation, 7 years). Of the 11 cases that underwent dedifferentiation, the interval between diagnosis and dedifferentiation ranged from 2 to 18 years (median time, 9 years; average time, 11 years). Six of the 11 patients showed dedifferentiated foci in the first recurrence, and three died of metastatic disease. Our study indicates that the behavior of well-differentiated liposarcomas is strongly influenced by location. Although the prevailing view is that dedifferentiation is restricted to tumors of the retroperitoneum, our study indicates that it is not a site-specific phenomenon, but is more likely a time-dependent phenomenon seen in situations with a high likelihood for clinical persistence of disease for a long period. Dedifferentiation identifies a tumor that is potentially more aggressive; yet the progression of the disease following dedifferentiation may be highly variable and probably depends on a number of factors, including the amount of dedifferentiation and type of therapy. Although atypical lipoma is an acceptable term for well-differentiated liposarcomas of the subcutis, it fails to convey the potentially life-threatening properties of retroperitoneal tumors. For these lesions as well as those in the deep soft tissues of the extremity, retention of the term well-differentiated liposarcoma is advocated.

Adult↗
PubMed1991

Salvage of proximal humeral amputations with a remnant forearm flap.

Spare-part surgery of upper extremity avulsions may facilitate primary soft-tissue healing and prosthetic rehabilitation. This procedure also may be applicable to the management of analogous proximal lower extremity avulsions where a short femoral stump and a shortage of soft tissue exist.

Arm Injuries↗
PubMed1991

Intraoral reconstruction with a microvascular peritoneal flap.

The microvascular peritoneal flap offers a new reconstructive option for closure of intraoral defects. The flap is easy to raise, and donor-site morbidity is low. Unlike fascial flaps, in which the raw surface may take weeks to "mucosalize," the peritoneal surface heals primarily. Finally, the rectus muscle effectively covers all forms of mandibular reconstruction, and the reliable skin paddle makes possible the closure of substantial cutaneous defects.

Fistula↗
PubMed1990

A survey of microsurgery training in the United States.

The increasing use of clinical and experimental microsurgical techniques has created a need for standardized, high-quality training programs in microsurgery. Toward this end, we conducted a study of the microsurgery instruction available in the United States. The data were collected from responses to surveys mailed to 55 microsurgery training centers across the country. Survey questions asked for a general characterization of each training program and its participants and for a specific description of course content. The results indicated that, even though training programs differed considerably, there were common elements. Total course length ranged from less than 40 hours to 80 hours, with a range of 32-40 hours devoted to basic microsurgery techniques. Forty percent of instructional programs were not certified for continuing medical education (CME) credit. Half of all reported trainees were residents in training. The basic microsurgery techniques common to most programs included instruction in microvascular end-to-end and end-to-side anastomoses of femoral arteries and veins in rats. Instruction in peripheral nerve repair was not offered. We conclude that, although there are merits to a diverse curriculum, it is time to institute a minimum level of standardized basic microsurgery training.

Curriculum↗
PubMed1990

Superoxide dismutase and catalase in skin flaps during venous occlusion and reperfusion.

We studied the enzymatic concentrations of superoxide dismutase (SOD) and catalase (CAT) in rabbit abdominal island skin flaps during 8 and 10 hours of venous occlusion followed by 4 hours of reperfusion. A correlation between such enzyme activity at the end of ischemia and flap viability was tested. The results show that the accumulation of blood and blood-derived substances cause enzyme activity to increase considerably during venous occlusion. The amount of increase was similar for both 8- and 10-hour venous occlusion. "True tissue enzyme activity" (corrected for the contribution of blood and blood-derived substances) remained constant during venous occlusion, suggesting that the availability of scavenging enzyme does not correlate with ultimate flap viability. During early reperfusion, however, both SOD and CAT activity decreased, suggesting that membrane damage leads to an increase in membrane permeability and to the loss of intracellular enzymes.

Animals↗
PubMed1990

Simultaneous reconstruction of cervical soft tissue and esophagus with a gastro-omental free flap.

A microvascular transfer of gastric tube and omentum was used to simultaneously reconstruct cervical soft-tissue and esophageal defects in five patients. All patients had previous high-dose radiation and multiple flap reconstructions. The largest esophageal and soft-tissue defects were 10 cm and 160 cm2, respectively. All wounds healed primarily except for one orocutaneous fistula. There was one death from an intraoperative stroke. The gastro-omental flap is useful in cases where the reconstructive surgeon is faced with both esophageal and soft-tissue defects--particularly in heavily irradiated patients who have few reconstructive options.

Anastomosis, Surgical↗
PubMed1990

Cytotoxic therapy. Role of durable venous access.

Aggressive chemotherapy regimens and supportive measures in haemato-oncology patients demand reliable venous access. Experience with this method in India has been limited. During a period of six months, we have used 42 subclavian indwelling catheters and 31 cubital Cavafix long lines. The mean age of patients in the two groups was 32 years and 7 years respectively. Subclavian catheters had a median duration of catheter placement of 46 days (range 4-145) and total 1494 catheter days, while cubital longlines yielded a median duration of insertion of 14 days (range 4-27) and total 508 catheter days. Catheter related complications were infection in 25% of patients, thrombophlebitis in 22%, blockade in 12% and misplacement in 17% in both groups taken together. The patients and families were extremely satisfied with the devices. Our experience supports further use of durable venous access in cancer patients. Implanted central venous catheters should be preferred whenever feasible.

Adolescent↗
PubMed1989

Rotational muscle flaps: a new technique for covering infected vascular grafts.

Twenty-one patients with established localized infection of vascular bypass grafts were treated with aggressive debridement and rotational muscle flap coverage to control graft infection. There were six gram-positive, six gram-negative, four mixed, and three fungal graft infections. Graft material included Dacron, Gore-Tex (registered trademark of W. L. Gore Associates Inc., Elkton, Md.), Dacron and Gore-Tex in combination, and saphenous vein. Twenty of 21 patients had successful preservation of graft function, local wound healing, and control of infection. There were no amputations or deaths. The one failure was caused by incomplete debridement of an infected graft segment. Aggressive debridement and rotational muscle flap coverage is an effective means of treating locally infected vascular bypass grafts.

Adult↗
PubMed1989

Coverage of acute vascular injuries of the axilla and groin with transposition muscle flaps: case reports.

Acute axillary or groin vascular injuries caused by farm machinery or shotgun blasts are often associated with extensive soft-tissue loss. Coverage of the repaired blood vessels with healthy tissue is necessary to avoid infection, desiccation, pseudoaneurysm, and rupture. Adjacent muscles are not always available to rotate for coverage, due to unacceptable functional loss, or injury to the principal vascular pedicle. We used proximally based trunk musculature with vascular pedicles out of the areas of injury to achieve coverage of four extensive axillary wounds and one extensive groin wound. Arterial repair only was performed in three axillary wounds. Combined arterial and venous repair were performed in one groin wound and one axillary wound. Followup ranging from 9 months to 5 years revealed no vascular failure or soft-tissue complications. We conclude that coverage of vascular repairs and soft-tissue defects with viable muscle is necessary in cases of extensive injury. Adjacent muscle is preferred for coverage, but when this is unavailable, coverage can still be achieved using more proximally pedicled muscles of the trunk.

Adolescent↗
PubMed1988

Accidental hand burns caused by operating room lights.

Three patients sustained burns of the hand in the operating room because of the lack of heat shields in the lights. A 54 degrees F increase in temperature in the operating field was noted when the heat shields were not in place.

Accidents↗
PubMed1988

Extravasation injury to the hand by intravenous phenytoin. Report of three cases.

Extravasation of intravenous phenytoin can result in serious soft-tissue complications. Three patients are presented, one of whom lost a hand. Assessment of circulation and early decompression fasciotomies may be necessary in such cases. Caution is recommended in the intravenous administration of phenytoin. Infusions at rates of less than 50 mg/min and education of nursing staff about this potential complication will decrease its incidence.

Amputation, Surgical↗