*3.1.2. Light-induced deposition*

Light source along with an electroless deposition process were used to deposit a Ni barrier layer. The phenomenon of a chemical reaction taking place is the same (catalytic oxidationreduction) as described in the previous section. However, the light source provided here helps in adjusting the electrochemical potential of the front are rear of the cell and enhances the plating rates [42]. The electron migration at the surface is controlled by the photo-voltage generated from the np-junction and the electronegativity of the substrates. Moreover, higher plating rates can be achieved as these photo-generated electrons enhance the reduction of the Ni2+ions on the silicon surface [15]. The increase in the plating rates due to light inclusion relives in the form of operating the bath at lower temperatures. Although a uniform Ni layer at higher plating rates can be deposited, the process of light-induced electroless plating involves complexity related to the process's characterization. Furthermore, the light-induced current in the LIP process helps to transport electrons only to the n-type surface, which limits the technique in metallizing n-type surfaces [43]. The light-induced nickel plating (LINP) process was also investigated by Yu-Han et al., and uniform Ni surfaces of high intrinsic quality were reported [44].

### *3.1.3. Laser-assisted deposition*

Laser-assisted deposition has also been used to employ the Ni deposition process on a silicon surface. The process is considered to be feasible for industrial applications, as the anti-reflection coating (ARC) layer can be ablated along with the Ni deposition. This can reduce the number of steps involved in cell processing and can help the development of solar cells with mass production on the industrial scale.

Here, an electrolyte solution is used where a cell composed of an np-junction is immersed and a laser beam is applied to pattern the grid at the wafer surface. The application of the laser beam increases the temperature in the solution and at the wafer surface [20]. The ARC is ablated due to the heat generated at the laser-exposed surface and increased temperatures in the electrolyte solution decompose the Ni particles. Furthermore, the light induced in the cell generates an electron-hole pair, the generated electrons support Ni deposition at the sample surface. The use of water containing Ni salts is considered to be useful for depositing the Ni layer on the silicon surface uniformly. There has been some progress reported regarding laser chemical Ni deposition by various research institutes [45-50], although the process still needs to matured. Laser chemical metal deposition (LCMD) is a solution for implementation on the industrial scale since ARC ablation along with Ni deposition can be performed at the same time. The LCMD process was successfully implemented at Fraunhofer ISE to form Ni-based Cu metallization with 17.9% efficient cells on CZ substrates [51]. Röder et al. also reported a laser-based method to deposit a Ni layer with thinner finger widths (< 30 μm) with a low temperature process known as 'laser transfer contact' (LTC) [52].


*<IP_ADDRESS> Technetium-99 m (99mTc) thyroid scans/radioiodine uptake scans*

Routine use of thyroid scintigraphy is not indicated in the assessment of goiter. A hot area in scintigraphy suggest benign lesion which can be of help to rule out malignant lesions when FNAC report of the thyroid nodules are equivocal. When TSH level is low and clinical features are suggestive of hyperthyroidism technetium-99 scan/Radio iodine uptake scan are useful to differentiate between Graves' disease, thyroiditis and toxic adenoma.

### **6. Treatment**

Treatment of goiter depends on whether TSH levels are normal or abnormal.

If TSH is elevated than normal, Levothyroxine supplementation is given for patient with overt hypothyroidism starting with a dose of 1.6 mcg/kg body weight per day in non-pregnant adults.

There are certain Indications for treatment of subclinical hypothyroidism like Anti-TPO positivity, menstrual irregularity, infertility, chronic kidney disease, pregnancy.

If TSH is less than normal range then the treatment modality depends on the nature of the illness in Graves' disease we have got three effective treatment modalities, i.e., thionamides (anti-thyroid drugs), radioiodine or surgery. Starting dose of Methimazole ranges from 10 to 40 mg per day in divided doses initially followed by single daily dose-Beta blockers are used for relief of tachycardia in non-asthmatic patients.

In multinodular goiter and toxic adenoma treatment modality is either radioiodine ablation surgery.

Iodine radioisotope I-131 is usually used for radioiodine ablation. It takes 6–18 weeks for thyroid tissue ablation post radioiodine administration. Treatment of subclinical hyperthyroidism is considered in patient older than age of 65 years and patient with other comorbidities like heart disease, osteoporosis, and postmenopausal women not on HRT.

Surgery is indicated in patients with large goiters with compressive symptoms, malignancy, and failed medical therapy.

#### **7. Conclusions**

The goiter is a known disorder affecting females more than males. It has various etiologies classified depending on the levels of TSH. The treatment of goiter is according to the etiology.

**11**

**Author details**

Sciences - BHU, India

Dhananjaya Melkunte Shanthaiah1

, Piyush Gupta2

2 Department of General Surgery, University of Massachusetts, Worcester, USA

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

1 Department of Endocrinology and Metabolism, Institute of Medical

\*Address all correspondence to<EMAIL_ADDRESS>
provided the original work is properly cited.

and Neeraj Kumar Agrawal1

\*

*Goiter: Overview of Aetiopathogenesis and Therapy DOI: http://dx.doi.org/10.5772/intechopen.90028*

The authors declare no conflict of interest.

**Conflict of interest**

*Goiter: Overview of Aetiopathogenesis and Therapy DOI: http://dx.doi.org/10.5772/intechopen.90028*


**2.2 Histopathological studies in ALS and neuroinflammation in retinal tissue**

(**Table 1**, **Figure 1**) Neuroinflammation is a pathophysiological mechanism, which involves the activation of astroglial and microglial cells, and it occurs in many neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, ALS, and glaucoma [62]. Microglial cells are the macrophages of the CNS and have the ability to respond to injury by becoming activated; they can proliferate, migrate, and change shape, acquiring an amoeboid appearance in the most active state [62, 71]. On the one hand, in an attempt to protect against damage, microglial cells can secrete proinflammatory molecules, such as interferon γ or interleukin (IL)-1β [62].

#### **Figure 1.**

 *Summary of retinal changes in amyotrophic lateral sclerosis. (A) Healthy retina. (B) Retinal changes in ALS. Most of retinal changes are mainly detected in the inner layers: (i) ganglion cell loss; (ii) activated microglia in outer plexiform layer (OPL) and inner layer complex (ILC) (constituting an inner plexiform layer and a nerve fiber–ganglion cell layer); (iii) p62-positive and TDP43-negative protein aggregates mostly in the inner nuclear layer with some in the ganglion cell layer (GCL); (iv) ubiquilin 2-positive inclusions mostly in the inner plexiform layer (IPL), with a smaller amount in the outer plexiform layer (OPL) and in the GCL; (v) periodic acid Schiff (PAS)-positive spheroids in the retinal nerve fiber layer (RNFL) and phosphorylated form of neurofilament (P-NF)-positive spheroids in the in the peripheral and peripapillary RNFL; (vi) non-phosphorylated form of neurofilament (NP-NF)-positive spheroids in the RNFL; (vii) hSOD1-positive vacuoles in in the IPL, with hardly any in the GCL and inner nuclear layer (INL).*

Nonetheless, uncontrolled activation of the M1 phenotype can lead to a state of chronic inflammation, which can induce neuronal death. On the other hand, microglial cells can also secrete anti-inflammatory molecules, such as IL-10 and the enzyme arginase 1 (Arg1), in order to control inflammation, repair tissue, and improve neuronal survival [ 62 , 71 – 73 ]. Consequently, activated microglia can acquire two different activation phenotypes: an M1 or proinflammatory phenotype vs. an M2 or anti-inflammatory phenotype, both of which can be influenced by molecules derived from surrounding cells such as astrocytes [ 62 , 74 ]. Astrocytes are glial cells of ectodermal origin that perform numerous functions for neuronal survival [ 75 ], such as maintenance of the volume and composition of the extracellular space, maintenance of the blood-brain barrier, and regulation of synaptic transmission [ 76 ], as well as metabolic maintenance and neuronal survival [ 77 , 78 ]. When astrocytes are damaged and consequently activated, "astrogliosis" occurs [ 79 ]. If this astrogliosis is severe, a glial scar may form [ 75 ]. Reactive astrocytes can interact with microglia and neurons and can impair the function of neurons after an injury [ 80 ].

 Astrocyte activation [ 81 ], microglial activation [ 82 ], and the appearance of lymphocytes [ 83 ] have been found in animal models of ALS (with SOD1 mutations) and in ALS patients. In ALS there are reactive microglia and astrocytes, which can result in motor neuron injury and subsequent death [ 73 , 74 , 81 ]. The SOD1G93A mouse model is one of the most suitable and widely used for preclinical studies in ALS, attributable to the animals having an analogous phenotype to patients. These animals develop limb paralysis due to the loss of motor neurons in the spinal cord, with a reduced lifetime of 150 days [ 84 ]. Microglial activation also occurs in ALS, as observed in SOD1-mutated mice and in spinal cord samples from ALS patients, which could exacerbate neuronal damage [ 73 , 74 , 81 , 85 ]. In fact, it has been shown that exogenous extracellular mutation of SOD1G93A is not directly toxic to motor neurons, but requires microglial activation for toxicity in primary motor neuron and glia cultures [ 86 ]. Furthermore, in SOD1 transgenic mice, activated astrocytes and microglia have been shown to contribute to disease progression but not to disease

#### *Retinal Disorders in Humans and Experimental ALS Models DOI: http://dx.doi.org/10.5772/intechopen.107052*

onset [87–89]. In ALS, microglial activation and proliferation have been observed in areas of significant motor neuron loss, such as the motor cortex, brainstem motor nucleus, corticospinal tract, and ventral horn of the spinal cord [90–94], as well as in areas with mild degeneration [95]. Precisely, in postmortem spinal cord analysis of patients with advanced stages of ALS, reactive astrocytes were found in the dorsal and ventral horn of the spinal cord [96] and in the gray [97] and white matter [34] of the cerebral cortex. Similarly, reactive microglia were found in the motor nucleus of the brainstem, motor cortex, corticospinal tract, and ventral horn of the spinal cord [91]. Reactive microglia were also observed in vivo using the PET imaging technique C-PK11195, finding a close relationship between microglial activation and upper motor neuron damage, but not lower motor neuron injury [98]. Moreover, in the SOD1 model, it was confirmed that overexpression of the SOD1 mutation in glial cells contributes to motor neuron damage, and that the degree of neuronal injury depends on the degree of glial cell pathology [99]. Microglial cells of SOD1-mutated mice suffer different degrees of morphological changes from resting to macrophagic amoeboid forms [91]. Lastly, symptomatic SOD1 transgenic mice also have increased numbers of microglial cells, mainly due to the proliferation of resident microglia [100].

Bearing in mind all of the above, both the microglia and the astrocytes play an important dual role in the progression of the ALS. Nevertheless, most studies about the involvement of microglia in ALS have been conducted in the motor cortex, brainstem motor nucleus, corticospinal tract, and ventral horn of the spinal cord. To our knowledge, there are only three studies that investigated the glial cells of the retina in relation to ALS [101–103].

In the first one, a mouse model of ALS devoid of RAN-binding protein 2 (Ranbp2), microglial activation was confirmed. Ranbp2 is a protein, which plays an important role in nucleocytoplasmic transport and whose regulation is affected in both sporadic and familiar ALS [104]. In this ALS mouse model, there was microglial activation with an increase in the number of microglial cells surrounding retinal ganglion cells (RGCs), as well as a noteworthy increase in amoeboid forms relative to controls. In addition, there was an increase in metalloproteinases in RGCs, and both hypertrophy in RGCs and axonopathy in the optic nerve were found [102].

In the second model, a TG mouse model of ALS SOD1 (SOD1G93A), there was a vacuolization, with hSOD1-positive vacuoles placed in the dendrites of excitatory retinal neurons, which were detected principally in the inner plexiform layer (IPL) and hardly in the GCL and INL; however, no signs of activation of either the astroglia or the microglia of the retina were shown compared with to the wild-type mice [101]. However, the authors did not rule out the possibility that the microglia were undergoing functional changes (in cytokines) related to the inflammatory process. Nevertheless, neuronal changes observed in this SOD1G93A ALS model in the brain at 50 days of age were followed by microglial morphological changes at 60 days [105–107]. Therefore, the authors concluded that, if there is an inflammatory process in the retina, microglia would be in a different, less reactive or even neuroprotective phenotype [101].

Lastly, the third transgenic murine SOD1G93A model of ALS in an advanced stage of the disease (120 days) showed a loss of the number of Brn3a+ RGCs and a microglial activation in retinal tissue [103]. Signs of microglial activation were found in different retinal sectors (superior, inferior, nasal, and temporal) of different retinal layers: outer plexiform layer (OPL) and inner layer complex (ILC) (constituted by an inner plexiform layer and a nerve fiber–ganglion cell layer). In addition, the microglial activation in this SOD1G93A model of ALS showed a cell thickening in the area occupied by each microglial cell, a significant increase in the area of microglial

arborization with hyper-ramifications in the inferior sector of the OPL, retractions of cell processes, and migration and clustering of cells in some areas of the retina, but no increase in the number of microglial cells [103]. Moreover, phenotypic analysis of the microglia showed an M1 phenotype or proinflammatory state of microglia, as the cells were intensely labeled with anti-IFNγ and anti-IL-1β but did not stain with the characteristic M2 markers (anti-arginase 1 and anti-IL-10) [103]. The significant decrease in the total number of Brn3a<sup>+</sup> RGCs at 120 days of illness would be consistent with the damage observed in the RGCs of the ALS models discussed above [37, 101, 102], as well as with the thinning of the peripapillary retinal nerve fiber layer (pRNFL), observed by OCT, in ALS patients compared with controls [36–44]. Consequently, these data would support that, in ALS, not only are motor neurons affected but also RGC loss occurs, considering this disease as a multisystemic disease [103].

In none of the abovementioned models were changes in the outer segments of the photoreceptors found. This could indicate that neither this layer of the retina nor the outer blood-retinal barrier (BRB) would be compromised in these animals. Because, when the outer BRB is disrupted, as in a glaucoma model of laser-induced ocular hypertension, there are morphological changes and an increase in the number of microglial cells in the photoreceptor outer segment layer [108–112]. Moreover, no changes in the number of microglial cells were found in either the OPL or the ILC [101, 103]; however, the group of Rojas et al. described signs of microglial activation [103]. This difference in results in the same experimental model could be due to the fact that Ringer et al. [101] used retinal sections, while Rojas et al. [103] used retinal whole mounts.

As mentioned above, microglial cells have two distinct phenotypic states that can exert neurotoxic or neuroprotective responses depending on the physiological conditions in which they are found. During ALS progression, activated microglia represent a continuum between the neuroprotective M2 phenotype and the neurotoxic M1 phenotype [113]. In SOD1 ALS animal models, in early stages of the illness, microglia in the lumbar spinal cord expressed markers related to the M2 neuroprotective phenotype (Ym1 and CD206); however, in the late stages of the disease, microglia in the lumbar spinal cord expressed markers related to the M1 neurotoxic phenotype (high levels of NADPH oxidase 2 (NOX2)) [74], suggesting that there is a polarization from a neuroprotective phenotype to a cytotoxic phenotype that induces motor neuron damage. In the retina, there is only one study that analyzed whether microglia are in an M1 or M2 activation phenotype [103]. The results of this study showed that, in 120-day-old SOD1G93A mice, microglia were strongly labeled with antibodies against M1 inflammatory cytokines (IFNγ and IL-1β), but not with those against M2 anti-inflammatory cytokines (arginase-1 and IL-10), suggesting that at an advanced stage of the disease retinal microglial cells are in an M1 activation phenotype or in a pro-inflammatory state that could be neurotoxic to RGCs, as demonstrated by the loss of these neurons. These results are consistent with the findings in spinal cords of the same animal model, where microglia in an advanced stage of the disease showed a neurotoxic M1 phenotype, demonstrating the dual role (neuroprotective/neurodegenerative) of microglial cells during the ALS process [74]. Therapeutic approaches that target microglia polarization and result in the induction of the M2 phenotype are promising strategies to ameliorate local neurodegeneration and clinical outcome of the disease [114].

#### **2.3 Histopathological studies in ALS and retinal spheroids and axon pathology**

(**Table 1**, **Figure 1**) Alterations in axonal transport (retrograde and anterograde) are a hallmark of ALS, being impaired both in ALS patients and in mutant SOD1

#### *Retinal Disorders in Humans and Experimental ALS Models DOI: http://dx.doi.org/10.5772/intechopen.107052*

mice. In the spinal motor neuron axons, an accumulation of altered mitochondria, neurofilaments, and autophagosomes [12, 58] was demonstrated. On the one hand, mutated dyneins in ALS mice cause this accumulation in the axons of mitochondria and autophagosomes [58]. On the other hand, altered autophagosomes do not eliminate either altered mitochondria or dilated endoplasmic reticules, which accumulate in the axons of motor neurons and cause them to malfunction [12].

There is only one study that focused on this important pathological mechanism in the retina [115]. This study analyzed retinal sections of postmortem eyes from ALS patients with periodic acid Schiff (PAS) and phosphorylated (P-NF) and nonphosphorylated (NP-NF) forms of neurofilament (NF), compared with age-matched controls. Three kinds of spheroids were revealed. First, PAS-positive spheroids with a diameter bigger than 9.07 μm in the retinal nerve fiber layer (RNFL) were observed in most ALS patients (but only in half of controls), most commonly in the pRNFL and the peripheral RNFL, but rarely in the central RNFL in patients with ALS. The density of PAS-positive spheroids was significantly greater in the pRNFL. Second, P-NF-positive spheroids ranging from 8 to 15 μm in diameter were observed in the peripheral and pRNFL only in ALS patients. Additionally, ALS patients showed a stronger P-NF signal intensity in the RNFL in the peripheral, central, and peripapillary regions. Third, NP-NF spheroids ranging from 7 to 10 μm in diameter were observed in the RNFL in some of ALS patients (but not in controls). In addition, in most of the ALS patients, the NP-NF signal was increased in the RNFL and IPL. Nevertheless, there was no significant correlation of these retinal spheroids and axon pathology with the clinical characteristics of the ALS patients (age at death, gender, disease duration, mode of disease onset, revised ALS functional rating scale, and rate of disease progression) [115].

Consequently, patients with ALS show not only hallmark findings in spinal cord motor neurons pointing to disrupted axon transport [116–121] but also retinal spheroids and axon pathology as a shared pathogenesis [115].  Parallel vessel pathology in the retinal and cerebral small blood vessels has been demonstrated in many systemic diseases such as coronary heart disease [126] or stroke [127], as well as in some neurodegenerative diseases such as Alzheimer's disease [128, 129] (even in subjects at high genetic risk of developing Alzheimer's disease [130]) and Parkinson's disease [131].

Some ALS-induced changes have also been described in small blood vessels of the brain, which include a loss of pericytes, endothelial cell degeneration, capillary leakage, downregulation of tight junction proteins, and microhemorrhages in patients with ALS [132, 133]. Moreover, alterations of the structure of small blood vessels of the skin and muscles in ALS patients have been described [134, 135].

There was only one study that analyzed retinal vessel pathology in ALS patients with Spectralis OCT but not with angio-OCT. This study described a thicker outer wall of retinal vessels in ALS patients compared with controls, which may be related to the findings in small blood vessels in skin and muscle biopsies. There were neither significant differences in the vessel diameters between ALS patients with spinal onset and bulbar onset, nor a correlation between the vessel measurements and clinical parameters (disease duration and ALS Functional Rating Scale—Revised (ALSFRS-R)) [136].


**3. Safety Evaluation in the Phase 1 Clinical Trial as PO**

The greatest advantage associated with delpazolid is its safety. In phase 1a of a phase 1 clinical trial to evaluate its safety, as illustrated in Table 1, 64 subjects were divided into eight groups, six of whom were administered delpazolid and two who were administered the placebo. The study was the first double-blind, randomized human trial of delpazolid. To deliver single-ascending-doses (SADs), delpazolid was administered in a step-wise manner from 50 mg up to 3200 mg. Only mild adverse events were observed up to 2400 mg. At a delpazolid dose of 3200 mg, gastrointestinal (GI) tract-related adverse events were noted. In the 3200 mg dose group, volunteers had to ingest 16 tablets of 200 mg delpazolid tablets at once, resulting in GI tract-related adverse events. Therefore, the maximum tolerated dose of delpazolid was determined to be 2400 mg per day.

**Table 1.** Summary of phase 1a/b and 2a dose-escalation study to assess the safety, tolerability, and pharmacokinetics of delpazolid as a single agent.

Dose-escalation process consisted of a single-ascending-dose phase (SAD) and multiple-ascending-dose phase (MAD). MTD, maximum tolerated dose; QD, quaque die (daily); BID, bis in die (twice per day); SAE, serious adverse event; EBA, early bactericidal activity; HRZE, isoniazid (H), rifampin (R), pyrazinamide (Z), and ethambutol (E). *a* Results were not yet published.

A phase 1b study was conducted based on multiple-ascending-doses (MADs) over seven days. Thirty-two subjects were divided into eight groups, six of whom were administered delpazolid and two of whom were administered the placebo. Subjects were given delpazolid in MADs from 400 mg BID (bis in die, twice a day) up to 1600 mg BID over seven days. Doses up to 1200 mg BID for seven days were well-tolerated with no specific adverse events observed. After the 7-day MAD study, a 21-day MAD study was conducted to evaluate bone marrow toxicity, which is one of the most critical side effects of linezolid [8]. Subjects administered 800 mg once a day (QD) to 1200 mg BID delpazolid were monitored for up to three weeks to more accurately assess adverse events such as myelosuppression, as signs such as decreased platelet count may be observed even after two weeks. As illustrated in Table 1, serious adverse events were not observed under the MAD-21-day condition. In summary, no myelosuppression-related adverse events or serious adverse events were observed in phase 1a with SADs up to 2400 mg and in phase 1b with MAD up to 1200 mg BID (2400 mg per day) for 21 days. Therefore, delpazolid does not appear to exhibit adverse events associated with repeated dosing. In addition, delpazolid did not cause CYP-mediated metabolism and cardiac repolarisation issues [6,9–11].


*2.1. Fucoxanthin Increases Expression of GCLC and GSS at the mRNA and Protein Levels*

HaCaT cells were treated with various concentrations of fucoxanthin for 12 h. The mRNA levels of GCLC and GSS in fucoxanthin-treated cells increased, demonstrating that 20 ΐM of fucoxanthin caused the maximal induction both in GCLC and GSS expression (Figure 1A). Next, HaCaT cells were treated with 20 ΐM fucoxanthin for various amounts of time. The mRNA levels of GCLC and GSS were highest at 12 h of treatment (Figure 1B). Furthermore, when HaCaT cells were treated with various concentrations of fucoxanthin for 12 h, the protein levels of GCLC and GSS increased, exhibiting that 20 ΐM of fucoxanthin induced maximal in GCLC and GSS expression (Figure 1C). Treatment with

20 ΐM of fucoxanthin for 12 h markedly increased the protein levels of GCLC and GSS (Figure 1D). These results indicate that fucoxanthin treatment increases expression of GCLC and GSS at both the mRNA and protein levels.

**Figure 1.** Effects of fucoxanthin treatment on the mRNA and protein expression of glutamate-cysteine ligase catalytic subunit (GCLC) and glutathione synthetase (GSS) in HaCaT cells. Cells were incubated with various concentrations of fucoxanthin (0–20 ΐM) for various amounts of time (0–24 h). The mRNA levels of GCLC and GSS were detected by reverse transcription-PCR (RT-PCR) following treatment ( **A**) with various concentrations of fucoxanthin for 12 h; and ( **B**) with 20 ΐM fucoxanthin for various amounts of time. The protein levels of GCLC and GSS were detected by Western blotting following treatment ( **C**) with various concentrations of fucoxanthin for 12 h; and ( **D**) with 20 ΐM fucoxanthin for various amounts of time. **\*** and **#** indicates significantly different from control of GCLC and GSS, respectively ( *p* < 0.05).