Hormesis: A General Biological Principle

Hormesis drives biological modifications from cells to higher levels of biological organization and emerges as a general basic principle of biology, integrating evolution, ecology, medicine, physiology, toxicology, and public health.

Stem Cell Theory of Cancer: Origin of Tumor Heterogeneity and Plasticity

In many respects, heterogeneity is one of the most striking revelations and common manifestations of a stem cell origin of cancer. We observe heterogeneity in myriad mixed tumors including testicular, lung, and breast cancers. We recognize heterogeneity in diverse tumor subtypes in prostate and kidney cancers. From this perspective, we illustrate that one of the main stem-ness characteristics, i.e., the ability to differentiate into diverse and multiple lineages, is central to tumor heterogeneity. We postulate that cancer subtypes can be meaningless and useless without a proper theory about cancer's stem cell versus genetic origin and nature. We propose a unified theory of cancer in which the same genetic abnormalities, epigenetic defects, and microenvironmental aberrations cause different effects and lead to different outcomes in a progenitor stem cell versus a mature progeny cell. We need to recognize that an all-encompassing genetic theory of cancer may be incomplete and obsolete. A stem cell theory of cancer provides greater universality, interconnectivity, and utility. Although genetic defects are pivotal, cellular context is paramount. When it concerns tumor heterogeneity, perhaps we need to revisit the conventional wisdom of precision medicine and revise our current practice of targeted therapy in cancer care.

Split cord malformations: A two years experience at AIIMS

Background:

Over a 2-year period, 2008-2009, a total of 53 cases of split cord malformation (SCM) were treated at the All India Institute of Medical Sciences (AIIMS). This study is a retrospective analysis of clinical features, radiological findings, and surgical outcome of these patients.

Materials and Methods:

During this period, 53 cases of SCM were treated at AIIMS. They constitute around 27% of all spinal dysraphism surgeries performed at the department of Neurosurgery, AIIMS; as 200 cases of spinal dysraphism were operated during the study period. The data was obtained from case files, operation notes, discharge summaries, and follow-up files.

Observations:

There were 30 cases of SCM type I and 23 cases of type II SCM. Seven patients were adult above 18 years of age. Except 7 patients, remaining 46 were symptomatic. Bony deformity of spine was recorded in 24 patients; of them, 19 had scoliosis and 4 had kyphosis. Deformity of foot was recorded in 10 patients. Thirteen patients had hypertrichosis, while four had dermal sinus. Magnetic resonance imaging (MRI) was performed in all patients. MRI revealed syringomyelia in 14 patients; however, only one patient had associated Chiari malformation. Six patients had meningomyelocele. Intra-operative; thick filum was noticed in 10 cases and in another 9 cases, there was filum lipoma. Dermoid was encountered in 4 patients, one patient had epidermoid tumor. Site of split was thoracic in 22, followed by lumbar region in 21 patients. Only 3 patients had split in cervical spinal cord. Seven patients had two separate splits at two different levels. Two patients had posteriorly located bony spur. All patients underwent surgery. Seven patients, those who had no neurological deficits pre-op, remained unchanged post-op. Amongst the 46 patients who had preoperative neurological deficits, eight had neurological deterioration post-op; five had deterioration in motor power and three had urinary problem. Five of these patients had type Id split, 2 had type Ic split, and one had type Ib split. However, among 8 patients who deteriorated post-op, four improved to preoperative status by the time of discharge. Thus, 4/53(7%) patients had long-term deficits, all with type Id split. Follow-up data was available for 36 patients (68%) and mean follow-up period was 12 months (range 6-24 months). Follow-up MRI revealed decrease in syringomyelic cavity in 6 of the 14 patients (44%) who had syringomyelia on preoperative MRI scans.

Conclusion:

Overall, SCM is an uncommon condition. In all cases of progressive scoliosis, MRI must be carried out. We subjected all asymptomatic patients to surgery and none developed post-op deterioration. Overall post-op neurological deterioration was noticed in 15% patients, of which 8% had transient post-operative deterioration. The new Type I SCM subclassification system proposed by Mahapatra and Gupta is found to have a significant prognostic value in assessing post-operative neurological deterioration in patients with type I SCM.

Do abundance distributions and species aggregation correctly predict macroecological biodiversity patterns in tropical forests?

AIM

It has been recently suggested that different 'unified theories of biodiversity and biogeography' can be characterized by three common 'minimal sufficient rules': (1) species abundance distributions follow a hollow curve, (2) species show intraspecific aggregation, and (3) species are independently placed with respect to other species. Here, we translate these qualitative rules into a quantitative framework and assess if these minimal rules are indeed sufficient to predict multiple macroecological biodiversity patterns simultaneously.

LOCATION

Tropical forest plots in Barro Colorado Island (BCI), Panama, and in Sinharaja, Sri Lanka.

METHODS

We assess the predictive power of the three rules using dynamic and spatial simulation models in combination with census data from the two forest plots. We use two different versions of the model: (1) a neutral model and (2) an extended model that allowed for species differences in dispersal distances. In a first step we derive model parameterizations that correctly represent the three minimal rules (i.e. the model quantitatively matches the observed species abundance distribution and the distribution of intraspecific aggregation). In a second step we applied the parameterized models to predict four additional spatial biodiversity patterns.

RESULTS

Species-specific dispersal was needed to quantitatively fulfil the three minimal rules. The model with species-specific dispersal correctly predicted the species-area relationship, but failed to predict the distance decay, the relationship between species abundances and aggregations, and the distribution of a spatial co-occurrence index of all abundant species pairs. These results were consistent over the two forest plots.

MAIN CONCLUSIONS

The three 'minimal sufficient' rules only provide an incomplete approximation of the stochastic spatial geometry of biodiversity in tropical forests. The assumption of independent interspecific placements is most likely violated in many forests due to shared or distinct habitat preferences. Furthermore, our results highlight missing knowledge about the relationship between species abundances and their aggregation.

Stem Cell Theory of Cancer: Rude Awakening or Bad Dream from Cancer Dormancy?

To be dormant or not depends on the origin and nature of both the cell and its niche. Similar to other cancer hallmarks, dormancy is ingrained with stemness, and stemness is embedded within dormancy. After all, cancer dormancy is dependent on multiple factors such as cell cycle arrest, metabolic inactivity, and the microenvironment. It is the net results and sum effects of a myriad of cellular interactions, interconnections, and interplays. When we unite all cancer networks and integrate all cancer hallmarks, we practice and preach a unified theory of cancer. From this perspective, we review cancer dormancy in the context of a stem cell theory of cancer. We revisit the seed and soil hypothesis of cancer. We reexamine its implications in both primary tumors and metastatic lesions. We reassess its roles in cell cycle arrest, metabolic inactivity, and stemness property. Cancer dormancy is particularly revealing when it informs us about the mysteries of late relapse, prolonged remission, and second malignancy. It is paradoxically rewarding when it delivers us the promises and power of cancer prevention and maintenance therapy in patient care.

Alterations in mitochondrial functions and morphology in muscle and non-muscle tissues in type 1 diabetes: implications for metabolic health

NEW FINDING

What is the topic of this review? Evidence of impaired mitochondrial functions and/or morphology in people with type 1 diabetes across various organ systems. What advances does it highlight? Impairments to mitochondrial functions and morphology may be a primary mechanism underlying the pathophysiology of various complications in people with type 1 diabetes.

ABSTRACT

We recently made the observation that there are significant alterations to the ultrastructure and functions of mitochondria in skeletal muscle of people with type 1 diabetes (T1D). These alterations are proposed to lead to decreased energy production in skeletal muscle during exercise and thus may contribute to the impaired aerobic exercise capacity reported in some people with T1D. This Symposium Review summarizes the evidence that similar alterations also occur in the mitochondria present in organ systems outside skeletal muscle in people with T1D, and that this may contribute to the development and progression of the known complications of T1D, which eventually lead to the reported premature mortality.

Split cord malformation with dorsally located bony spur: Report of four cases and review of literature

Split cord malformations (SCM) with a dorsally located bony spur are a very rare entity. The authors report a series of four such cases. The literature is reviewed regarding the pathogenesis and management of this uncommon variant of SCM. The presenting features include - scoliosis with motor and autonomic dysfunction (n = 1), scoliosis with cutaneous patch (n = 1), hypertrichotic area (n = 1), and motor deficits alone (n = 1). The location of spur was thoracic and lumbar in two patients (50%) each. Low-lying conus was present in three patients. Long segment syrinx was present in one patient. With respect to the bony anomalies, two patients had a hypertrophied posterior arch (HPA) and one patient had a dysraphic spine. All patients underwent surgical excision of the spur with detethering, if a low-lying conus was present. Two patients developed transient worsening of the neurological status after surgery which recovered at the time of the last follow-up; in both these patients, there was a HPA and a low-lying conus. Surgical excision of the spur with detethering of filum, in cases of low-lying conus, is the treatment of choice. Risk of post-operative worsening of the neurological status is increased in cases in which there is concomitant presence of HPA.

Flexural Strength Evaluation of Multi-Cell Composite T-Shaped Concrete-Filled Steel Tubular Beams

The multi-cell composite T-shaped concrete-filled steel tubular (MT-CFST) element is an innovative structural form. It has great potential for construction applications because of favorable advantages over traditional composite elements. The flexural strength of MT-CFST beams was investigated in this study to provide recommendations in line with existing design codes. First, formulations to evaluate the flexural strength of MT-CFST beams were derived based on the Unified Theory and plastic stress distribution method (PSDM). For the Unified Theory-based formula, a modified confinement effect factor that considers the shape of a cross-section was proposed. An experimental study on the flexural behavior of six MT-CFST beams as well as two hollow section counterparts was conducted. The influence of bending moment direction, concrete infill, wall thickness, and cross-section sizes were investigated. The accuracy of the proposed formulations was verified against the test results and numerical results from finite element modeling. The comparisons showed that the formula in line with the Unified Theory provided more accurate predictions with reasonable conservatism for the studied MT-CFST beams.

Development of a tibial intraneural ganglion cyst after surgery on a peroneal intraneural ganglion in a pediatric patient: further support for the articular origin of intraneural ganglion cysts. Illustrative case

BACKGROUND

The articular origin of intraneural cysts has been previously described and well supported. Intraneural ganglion cysts most commonly occur in adults and in the common peroneal nerve arising from the anterior aspect of the superior tibiofibular joint (STFJ).

OBSERVATIONS

The authors report a pediatric patient who developed a tibial intraneural cyst arising from the posterior aspect of the STFJ within months after surgical treatment of a peroneal intraneural cyst from the anterior aspect of the same joint. Surgery consisted of disconnecting the articular branch of the peroneal nerve and decompression of the cyst. Three-month postoperative magnetic resonance imaging showed resolution of the peroneal intraneural cyst and anterior compartment denervation but demonstrated a clinically occult small tibial intraneural ganglion cyst arising from the STFJ with popliteus muscle atrophy.

LESSONS

This case underscores the importance of addressing the underlying etiology (articular synovitis) or the communication pathways (articular branches) whenever feasible to mitigate intraneural cyst recurrence. Furthermore, this report reinforces the validity of the articular theory. https://thejns.org/doi/10.3171/CASE24277.

An intraneural ganglion cyst of the dorsal cutaneous branch of the ulnar nerve arising from the wrist: support for the articular origin. Illustrative case

BACKGROUND

The articular theory of the formation of intraneural cysts has significant supporting evidence at common locations but has been less accepted at rarer sites. There have been only 5 cases in the literature documenting an intraneural ganglion cyst in the dorsal cutaneous branch of the ulnar nerve (DCBUN), with only 1 case documenting a joint connection. In this report, the authors present a second case with a proven joint connection in support of the articular theory.

OBSERVATIONS

The authors report the case of a 73-year-old man who developed a large intraneural ganglion cyst within the DCBUN along the palmar ulnar aspect of his left wrist. Magnetic resonance imaging demonstrated an articular connection to the distal radioulnar joint. During surgery, the intraneural ganglion cyst was resected and the articular branch was disconnected. The patient recovered and returned to work 4 weeks postoperatively.

LESSONS

This case further supports the articular theory as the explanation for intraneural ganglion cysts, even at unusual locations. https://thejns.org/doi/10.3171/CASE24569.

[Unified theory of electroseparations]

Linear electroseparations in vacuum, gas phase and liquid phase have created mass spectrometry, ion mobility spectrometry, electrophoresis and capillary electrophoresis. However, they have not systematized yet, developing independently, with their own theory, not related to each other. In this paper, unified motion equations were derived from the second law of Newtonian mechanics combined with electrostatic theory. From them, the general sub-equations of motion and measurement modes of all the above-mentioned methods were deduced and discussed briefly. These equations are not only helpful to systematize these existing methods but also are usable to deduce and discover novel electro-separation modes.

Split Cord Malformation Type 2 with Double Dorsal Lipoma: A Sequela or a Chance

An 11-month-old baby girl, with normal perinatal history, presented with a congenital lumbosacral swelling and a sacral dimple. Imaging revealed a split cord malformation (SCM) type 2 at L1–L3 with a lipomeningocoele extending intradurally and tethering both the hemicords, the conus was noted to be at L4. She underwent excision of the lipoma and detethering of the hemicords. Intraoperatively, the split cord was seen from L1 to L3 with an aberrant median vessel passing between the hemicords. Two lipomas were seen separately attached to each of the hemicords, the lipomas were dissected off the hemicords, and the hemicords were neurulated. The case helps revisit the unified theory proposed by Pang for SCM as well as the theory of premature disjunction in the pathogenesis of lipomeningocoele. Formation of the endomesenchymal tract splits the developing cord into two, whereas the premature detachment of neuroectoderm from the cutaneous ectoderm can lead to lipomeningocoeles. The present case is only the fourth case ever reported of an SCM type 2 with double lipoma. In the case report, we discuss the embryological basis of this condition and surgical nuances of management.