A case-control study of leukemia at a naval nuclear shipyard

A matched case-control study was conducted of 53 leukemia deaths and of 212 controls within a previously studied cohort of 24,545 on-shore workers employed between January 1, 1952 and August 15, 1977 at the Portsmouth (New Hampshire) Naval Shipyard. The study sought to ascertain a priori whether there was an association between leukemia deaths and occupational exposure to either ionizing radiation or organic solvents. To obtain information on individual exposures, radiation dose histories and detailed work histories by job and shop were evaluated for each subject. No statistically significant associations were found either between ionizing radiation or presumed solvent exposure and myelogenous or lymphatic leukemia. However, when specific job categories and shops were examined without benefit of a priori hypotheses, two occupations, electrician and welder, were found to be associated with leukemia. For electricians, the Mantel-Haenszel odds ratio (ORMH) was significantly elevated for all leukemias (ORMH = 3.00, 95% confidence interval (CI) = 1.29-6.98), particularly for lymphatic leukemia (ORMH = 6.00, 95% CI = 1.47-24.45). For welders, the odds ratio was not significantly elevated for all leukemias (ORMH = 2.25, 95% CI = 0.92-5.53), but was significantly elevated for myeloid leukemia (ORMH = 3.83, 95% CI = 1.28-11.46). These findings persisted when potential confounders were adjusted by means of a conditional logistic regression model.

Primary scalp cancer in Singapore

Cancers of the scalp are uncommon. Owing to their unique site they pose problems in surgical treatment. A retrospective study of all scalp cancers notified to the Singapore Cancer Registry over 17 years has shown that squamous cell carcinoma is the most common cancer followed by basal cell carcinoma. Other cancers are sweat gland carcinoma, angiosarcoma, dermatofibrosarcoma protruberans, liposarcoma, fibrosarcoma and malignant lymphoma. Scalp cancers are more common in Chinese and very rare in Indians. There is no difference in the incidence between the sexes. The surgical treatment and reconstructive techniques employed in 52 patients are described. When localised, scalp cancers are managed like other skin cancers but once they invade bone, they become aggressive and are difficult to eradicate. Wide radical excision provides cure and the skull bone if involved should be removed.

Congenital median clefts of the upper lip

This is a report of 12 cases of congenital median cleft deformity of the upper lip seen in the Department of Plastic Surgery, Singapore General Hospital. This deformity is extremely rare and there are probably not more than 100 cases reported in the literature. The classification, nomenclature, pathogenesis and embryological development of median clefts are still not clearly understood. An analysis of the 12 cases is made with the view to clarify the nomenclature and classification of median clefts. An attempt is also made to explain the embryogenesis of this deformity and its common association with cranial and other facial defects.

T-cell function in B-lymphocyte-deprived mice

Previous work has identified selective defect(s) in T cells in mice deprived of B lymphocytes by the chronic administration of anti-IgM antibody. Experiments described in the present communication revealed that anti-IgM-treated mice do not possess T cells with surface Ia and FcR, and, unlike T cells from normal animals, they also fail to bind these molecules in vitro. Functional assays disclosed that an anti-suppressor pathway which relies on Ia+ donor and acceptor T cells is interrupted in these mice at both levels. These observations may provide an insight to explain the selective failure of some T cells when B lymphocytes have been deleted.

The role of fibreoptic bronchoscopy in the management of respiratory burns

We found that fibreoptic bronchoscopy was a useful, simple, safe and accurate method in the diagnosis of inhalation injury, determining the type, the site and the extent of damage sustained. The most common mucosal damage was erythema and oedema of the supraglottic and glottic tissues, though in a few cases more severe and extensive injury was seen. Death seemed to be determined largely by the extent of skin burn but since there did not appear to be a close relationship between the severity of skin burn and the presence of inhalation burn, we suggest that the two types of injuries be evaluated separately. The main therapeutic role lies in the assessment and anticipation of imminent upper airway obstruction caused by oedema of the supraglottic tissues and the glottis. Endotracheal intubation could then be carried out promptly. Changes in clinical features and laboratory results were too slow to be of use in the prediction of upper airway obstruction, but could be indirect indicators of lower and peripheral airway injury.

Surgical treatment of spontaneous cerebellar hemorrhage

Spontaneous cerebellar hemorrhage accounts for 5%-10% of intracerebral hemorrhage in most series. From June 1979 to June 1983 we had 26 surgical cases of spontaneous cerebellar hemorrhage. There were 15 men and 11 women. The typical history was sudden onset of severe headache, vomiting, dizziness, and inability to walk. Disturbance of consciousness was usually a late feature. Common signs were truncal ataxia, nystagmus, conjugate eyeball deviation, small miotic pupils with or without light reflex and abducens palsy. Surgical indications are (a) disturbance of consciousness, (b) signs of brainstem compression and (c) hematoma with transverse diameter greater than 3 cm. The overall surgical mortality was 34.6%. Twenty-two patients underwent suboccipital craniectomy to evacuate hematomas with or without ventriculostomy; mortality rate was 27%. Four patients underwent ventriculostomy only; mortality was 75%. Causes of death were (a) brainstem failure, six patients; (b) airway obstruction, one patient; (c) chest infection, one patient; (d) chronic renal failure, one patient.

CONCLUSION

(a) suboccipital craniectomy to evacuate the hematoma is the most effective procedure where treatment is indicated; (b) the clinical recovery of the survivors show that 31% return to work, 38% are moderately disabled but take care of themselves, and 31% remain dependent on others; (c) deeply comatose patients may still benefit from early operation.

Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. III. T-cell requirements for its induction

Immunogenic stimuli rapidly induce a potent mediator with antisuppressor activity which represents complexes of Ig and antigen. The formation of the complexes depends on the interaction of two T cells both of which bear the Ly1 phenotype. The two T cells can be separated on the basis of their sensitivity to antilymphocytic serum and dependency on the presence of thymus. T cells bearing I region coded determinants are essential for the formation of the mediator.

Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. I. Its regulation by I-A gene products

It has previously been demonstrated that within 6 hr after immunogenic stimulation the serum of mice contains a unique form of immunogenic antigen which represents complexes of Ig and antigen. The complexes are known to be strongly cytophilic for Ly2+ Ia+ FcR+ T cells and markedly enhance the IgG response. Anti-I-A treatment of mice suppresses the IgG antibody response and results in the generation of antigen specific T suppressor cells (Ts). Furthermore, anti-I-A treatment blocks the induction of the complexes and abolishes the enhancing effect the complexes exert on the IgG antibody response. The 6-hr cytophilic complexes were shown to block the function of Ts and allow a normal IgG response to take place; therefore, they act as mediators of a novel T-cell pathway called antisuppression. The blocking of the induction of the antisuppressor complexes by anti-I-A antibody was at least in part due to an effect on T cells. In conclusion, products of genes of the I-A subregion of the MHC control the activation early after immunization of a T-cell pathway which is called antisuppression since its major function is interference with the expression of suppression. Its early induction (within 6 hr) suggests that antisuppression may play a pivotal role in determining between immunity and unresponsiveness.

Activation in vivo of a major antisuppressor T-cell pathway immediately after immunization. II. T-cell requirements for its expression

Immunogens activate in vivo within 3-6 hr after injection a new and hitherto unrecognized T-cell pathway which interferes with T-cell suppression, therefore called antisuppression. An important soluble mediator with antisuppressor activity is detected in the serum of immunized animals within 3-6 hr. The mediator represents a unique form of complexes of Ig and antigen. The antisuppressor function of the complexes does not represent a direct "neutralizing" effect of the complexes on the effector T suppressor cells. The antisuppressor complexes activate an Ly2+ T cell which, with the interaction of an Ly123+ T cell, blocks completely T-suppressor-cell function. The biological significance of the T antisuppressor pathway is discussed.

Transoral anterior decompression for treatment of unreducible atlantoaxial dislocations

Three cases of nonreducible atlantoaxial dislocation are reported. Transoral anterior decompression followed by posterior fusion was done with good results in all three cases.

Skin effects of occupational kneeling

To evaluate chronic knee trauma associated with kneeling, we conducted a cross-sectional questionnaire survey among floorlayers and tilelayers, two trades that require kneeling. Bricklayers and millwrights were studied for comparison. Approximately 28% of the 432 questionnaire respondents volunteered for a subsequent medical examination. Ultimately, data were analyzed for 112 floorlayers, 50 tilesetters, and 235 "comparison" workers. We found that the history of past skin infection in the knee area was about four times more prevalent among floorlayers (7.1%) than among workers in the other two categories combined (1.8%). Unilateral or bilateral patellar skin thickening and erythema were found to be more prevalent among those who kneel: 79% of floorlayers and 98% of tilelayers vs 35% of the control group were found to have skin thickening; 52% of floorlayers and 49% of tilelayers vs 24% of the control group were found to have erythema on the frontal aspect of the knee.

Detection in vivo 6 hours after immunization of a mediator with possible antisuppressor activity

Immunization of mice with foreign proteins or particulate antigen induces the formation of immunoglobulin (Ig)-antigen complexes which are strongly cytophilic for T cells and have been shown recently to markedly enhance the 7 S antibody response. In this report we demonstrate that pretreatment of the animals with cyclophosphamide or anti-I-J antiserum eliminates the difference in the antibody response between the mice injected with the complexes and the controls, in other words, the enhancement. Six hours after allogeneic stimulation the serum of mice contains also a cytophilic (for T cells) Ig which most likely represents, as in the case of the foreign antigens, complexes of Ig with alloantigens. The allogeneically induced 6-h serum (6HS) contains a factor which enhances the cytotoxic T lymphocyte(s) (CTL) response in vivo. As with the 7S antibody response, pretreatment of mice with cyclophosphamide, in doses known to eliminate suppressor cell expression, "masks" the CTL enhancement of the allogeneically induced 6HS. The same result was also observed with the anti-I-J antiserum. In conclusion, the 6-h complexes in cyclophosphamide- and anti-I-J-treated mice do not produce a 7 S antibody or CTL response above that produced by the control group (no complexes). Using heat-treated allogeneic tumor cells, known to induce suppressor cells in vivo, we have shown that for a low dose of tumor cells, the allogeneically induced 6HS did not block the induction of suppressor cells, but completely blocked their function. These results suggest that the enhancement of both humoral and cell-mediated immunity by the 6HS (complexes) is likely to be due to interference with normal suppressor cell function, that is, an antisuppressor mechanism.

Intradural rupture of lumbar intervertebral disc

Two cases of intradural disc rupture with cauda equina compression are reported. Myelography demonstrated complete block and at surgery intradural fragments of sequestrated disc material were found. The pathogenesis of this condition is reviewed and our recommendation for management is presented.

Rehabilitation of burns of the upper limb

The authors wish to document the experience of the Burns Unit, Singapore General Hospital in the management of burns of the upper limb. Fifty-six patients with post-burn deformity of the upper limb seen during a five year period (July 1978-July 1983) were reviewed. The cases were analysed and there were no significant differences in age, sex and race distribution. There were 8 axillary contractures, 9 elbow contractures, 10 wrist deformities and 56 hand deformities. Anterior axillary skin fold contracture was the commonest deformity occurring at the shoulder, whilst cubital contractures were mainly found on the lateral aspect of the elbow. The elbow was the commonest site for periarticular heterotopic calcification. Wrist deformities included hypertrophic scars and contractures and they were frequently found on the dorsum of the wrist. A classification of post-burn hand deformity has been described and this was based on the site of the original injury. Burns involving the dorsum of the hand/fingers were subclassified into two groups depending on whether the extensor tendon was involved. The prognosis was good when there was no tendon injury, but when the extensor tendons were involved, poorer hand function resulted and this was reflected by the number of secondary operative procedures required. Flexion contractures were the commonest deformity found on volar burns. When both surfaces were burned the prognosis depended upon the burns depth. Digital burns treated surgically had fewer residual contractures. The role of occupational therapy, scar control, splinting and secondary surgery in relation to the rehabilitation of the burned upper limb is discussed in some detail.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary oral malignant melanoma

A fifteen year review (1968-1982) of all cases of malignant melanomas seen in Singapore revealed nine cases in the oral region. The cases were analysed and the literature reviewed. The cases usually presented late and the hard palate is the commonest site involved. The highest incidence is around the 4th-6th decade. Oral melanomas have a poorer prognosis when compared to cutaneous melanomas and this is similar to other reported series. No difference in sex incidence was seen in this series and the estimated incidence of oral to all other cases of malignant melanomas was about 6%.

A new approach to bilateral cleft lip repair

The basis of this new approach to bilateral cleft lip repair is the emphasis placed on a thorough understanding of the deformity itself and a detailed knowledge of the normal anatomy of the upper lip, especially that of the philtrum. A population survey has been carried out to determine what the normal philtral dimensions are at the different age groups relevant to the operation milestones in cleft lip surgery. A separate study to determine the histological basis of the philtral configuration has also been carried out. Based on the results obtained from these separate studies, a new approach and technique of bilateral cleft lip repair has been developed and applied to a series of 42 consecutive cases operated on by the author during the past 5 years.

Congenital cleft lip and palate in Singapore

Cleft lip and palate is the most common congenital abnormality seen in the Department of Plastic Surgery, Singapore General Hospital. A total of 461 operative cases seen over a period of 5 years (1977 to 1981) is analysed. There is a relatively high incidence in the Singapore population of 2.0 per 1000 live births. In both cleft lip and cleft palate deformities, there is no significant difference in the sex distribution. The cleft patterns show that 78% of the cases are unilateral clefts, 53% are left sided, 25% are right sided and 22% of the cases are bilateral clefts.

Pressure garments in the prevention and treatment of keloids

Hypertrophic scarring and keloids are frequent sequelae following trauma. Continuous and controlled pressure through the use of pressure garments can yield a high degree of non-surgical control of both hypertrophic scar formation and scar contracture resulting in soft, pliable scars with relief from itch and pain. This paper is a study of 280 patients, carried out in the Department of Plastic Surgery, Singapore General Hospital, over a period of 3 years. Not only are the results highly encouraging but the garments themselves are readily and simply constructed from locally available materials, using basic sewing skills.

Management of severe maxillo-facial injuries

Maxillo-facial injuries have increased in incidence in Singapore due mainly to road traffic accidents. Approximately 450 cases are seen annually in the Singapore General Hospital. A review of 50 consecutive cases of severe maxillo-facial injuries seen in the Department of Plastic Surgery showed that the majority were Lefort II type fractures (64%) followed by Lefort I fractures (14%) and Lefort III fractures (8%). There were seven cases which had a combination of multiple facial fractures. The significant associated injuries occurred in the limbs (32%), the head (30%) and in the chest (8%). The emergency management of maxillo-facial trauma is discussed in some detail and some of the problems in the treatment of severe or multiple facial fractures are also highlighted in this paper.

The pattern and management of traumatic soft tissue injuries of the lower limb

38 cases of soft tissue injuries of the lower limb seen in the Department of Plastic Surgery, Singapore General Hospital are reviewed. The pattern of soft tissue trauma reveals that the incidence is highest in the young male population between the ages of 20-30 years. Road traffic accidents are the commonest cause of trauma and the pedestrian is the most frequent victim. The commonest site of lower limb involvement is the leg and the majority of the cases of bone exposure following trauma are due to degloving injuries. The reconstructive procedures used include split-skin grafts, cross-leg flap, local transposition flap, muscle transposition flap, dorsalis pedis island flap and free groin flap. Split-skin graft and cross-leg flap procedures accounted for the management of 75% of the cases in this series.

Intra-oral minor salivary gland tumours--a study of 25 cases

This paper reviews our experience of minor salivary gland tumours seen jointly in the Departments of Plastic Surgery and Dental Surgery, Singapore General Hospital. Twenty-five cases seen over a period of five years are reviewed and the analysis of these cases show that there is (a) a predilection in the Chinese population to develop these tumours (b) a maximum incidence in the sixth decade (c) a higher incidence of benign tumours in females whilst the malignant tumours are equally common in both sexes (d) the palate is the commonest location of these tumours followed by the cheek and (e) the commonest histological types of malignant tumours are adenoid cystic carcinoma (28%) and muco-epidermoid carcinoma (16%). The malignant propensity of this group of tumours is emphasized as well as the need for adequate and radical primary resection to ensure better survival rates. The results in the present series are extremely encouraging and no recurrences have been noted but no claims are made regarding cure rates because long-term follow-up is necessary in this group of tumours due to late recurrences.

A case of angiosarcoma of the scalp

This is a report of a second case of angiosarcoma of the scalp occurring in an Oriental. In spite of surgical excision, radiotherapy and chemotherapy the tumour not only recurred but new lesions appeared. She developed liver metastases and died from chest complications 4 1/2 years after the initial presentation of the tumour. The clinical features, histology and treatment of angiosarcomas of the scalp are briefly discussed.

Acute mesenteric vascular occlusion: a review of 40 cases

Forty patients with mesenteric vascular occlusion were observed over a ten-year period. The main clinical findings were abdominal tenderness (in 80% of the patients), abdominal pain (in 83%), guarding and rigidity (in 60%) and vomiting. At operation, twelve patients (30%) had massive gangrene of the small and large bowel, 10 (25%) of the small bowel alone, and six (15%) had subsequent gangrene of the small bowel. Atherosclerosis with thrombosis of the superior mesenteric artery was found in 70% of cases, and embolism in 17.5%. Mortality was 77.5%. Nine patients (22.5%) who underwent resection survived.

Dual laser interferometer for plasma density measurements on large tokamaks

A two-wavelength plasma density interferometer utilizing a CO(2) laser and an HeNe laser is described. The interferometer is being designed for use on Doublet III, a large noncircular cross-section tokamak. The use of the two wavelengths allows the distinction between fringe shifts due to plasma density and fringe shifts due to mirror vibrations. Plasma density fringe shifts of 1/10 of a fringe shift can be measured in the presence of mirror vibrations which cause several fringe shifts. A simple digital phase comparing electronic system is used.

Single partition function for three phases

The significant structures theory of liquids has been extended to take into account (i) translational degrees of freedom in the degeneracy term and (ii) the perturbation term which becomes important near the critical region. With these improvements, the calculated thermodynamic properties of argon agree very well with experimental results from the melting point through the critical point, along the coexistence curve as well as along the critical isochore and for the solid and the vapor.

Magnetic circular dichroism of molecules in dense media: Spin-forbidden transitions of carbonyl molecules

The purpose of this paper has been to calculate the magnetic rotational strength of the spin-forbidden (1)A(1) --> (3)A(2) transition of the carbonyl group. For this purpose, simple molecular orbitals have been used and only one-center integrals have been considered. The calculated results have been compared with the experimental measurements.

Soluble factors in immune sera of mice. II. Reversible loss of surface immunoglobulin induced in vitro

Serum collected from BALB/c mice at different time intervals during primary immunization induces in vitro a decrease of Ig+ cells in short-term cultures of normal spleen cells. The decrease was shown to be caused by loss of surface immunoglobulin (Ig) for the following reasons: no cell loss was detected which coulc account for it; the number of Ig+ cells returned to normal levels when the serum was removed and the cells were cultured further in fresh medium. The serum activity was recovered in a fraction with molecular weight less than 10,000 Daltons. The factor was active at 4 degrees C and on cells treated with high doses of Con A. Only a portion (25-30%) of the Ig+ cells are affected by this factor since after the initial decrease no further changes were observed during the 7 hr culture period. No changes in the distrubution of surface Ig was detected by fluorescent techniques on the remaining Ig+ cells. This factor was detected as early as 6 hr after immunization but its concentration was found 4-fold higher on the 7th day.

Soluble factors in immune sera of mice. I. Specific and non-specific suppressive activity

Serum collected from mice 7 days following immunization with heterologous erythrocytes (SRBC, HoRBC) contained potent and specific immunosuppressive activity. When the serum was filtered through a Diaflo UM-10 membrane the activity was recovered in the filtrate, indicating that a factor less than 10,000 Daltons is responsible for it. Filtrates obtained from animals immunized with soluble antigens (BSA, POL) in FCA suppressed the 7S response to SRBC but had no effect on the 19S response. This non-specific suppressive effect on the7S response was also shown by filtrates obtained from sera of animals injected with FCA or other adjuvants (LPS, poly A:U). The 19S response to SRBC was either not affectd (LPS, poly A:U) or actually enhanced. (FCA). The SRBC-induced filtrates markedly suppressed the espression of DH to SRBC.

The function of T cells carrying receptors for complexes of Ig and antigen

Thymocytes exposed briefly in vitro to a variety of particulate substances (such as mycobacteria, erythrocytes of allogeneic cells) or to substances known to act in vivo as adjuvants (LPS or poly A:U), generate supernates which are able to induce cytophilic Ig in normal mouse serum in the presence of a foreign protein (antigen). This cytophilic Ig is taken up by 20-25% of splenic T cells. Hydrocortisone resistant thymocytes show the same property, while bone marrow cells are inactive. This activity is similar to that reported previously as being present in the 4S fraction of mouse serum, collected 6 hours after injection of complete Freund's adjuvant. It is proposed that this factor is responsible for the formation of complexes of Ig and antigen which have been detected in the serum 6 hours after immunization. Thymocytes collected 6 hours after priming in vivo with SRBC (when a subpopulation among them carries easily demonstrable surface Ig) are able to amplify markedly the antibody response particularly the 7S. It is postulated that the factor by generating the cytophilic Ig (complexes?) which is taken up by T cells, sets up a mechanism which markedly amplifies their helper cell function.

Comparative study of cytosine arabinoside therapy alone and combined with thioguanine, mercaptopurine, or daunorubicin in acute myelocytic leukemia

Three hundred twenty-six patients with acute myelocytic leukemia were randomly and prospectively assigned to four therapeutic regimens: cytosine arabinoside either alone or in combination with daunorubicin, 6-mercaptopurine, or 6-thioguanine. The results in 231 qualified previously untreated patients were analyzed. The combination treatments produced a significantly greater frequency of complete or partial remission than single drug therapy. Treatment with cytosine arabinoside and thioguanine led to 48% age-adjusted complete and partial responses. The median sur survival from diagnosis of all 66 evaluable patients treated with these two drugs was 18 weeks, while the median survival for those who responded to this combination was 15 months.

Acute mesenteric vascular occlusion: A review of thirty-two patients

High mortality rates associated with mesenteric occlusion are a tremendous challenge. We reviewed 32 patients admitted to Beckley Appalachian Regional Hospital during the years 1965 to 1974. The majority of the patients were men. There was quite a variation in the symptoms and physical signs, with heart disease commonly associated with mesenteric occlusion. Massive gangrene involving the small and large bowels had the worst prognosis. Thrombectomy and anticoagulation did not prove beneficial in our series. Patients who survived massive resection are having intermittent diarrhea, responsive to medical treatment. The mortality rate in this series of 32 patients was 81.3 percent. It is hoped that with increased use of mesenteric angiography, early diagnosis, and prompt management the mortality rate can be brought down to acceptable levels.

Magnetic Circular Dichroism of Molecules in Dense Media: Relation Between Magnetic Circular Dichroism and Hammett's Constants

The linear relation between the magnetic circular dichroism (benzene (1)A(1g) --> (1)B(2u) transition) of monosubstituted and 1,4-disubstituted benzenes and the substituent constants sigma and sigma(R) are compared. In all cases, better linear correlations were found between the magnetic circular dichroism and sigma(R). Three series of 1,4-disubstituted benzenes, XC(6)H(4)I, XC(6)H(4)NO(2), and XC(6)H(4)CO(2)H, have been chosen for the magnetic circular dichroism measurements.